Hello! Thank you, I already considered modifying the 420LCD file, but I finaly decided to try and write the routine myself. For practice. It has been 7 years since I last saw C and I think I need more practice. I find the struct {} and union{} confusing - can't make it work?! I know that one of those is what I am looking for. Regards! ----- Original Message ----- From: To: Sent: Sunday, May 28, 2006 6:02 PM Subject: Piclist Digest, Vol 22, Issue 33 > Send Piclist mailing list submissions to > piclist@mit.edu > > To subscribe or unsubscribe via the World Wide Web, visit > http://mailman.mit.edu/mailman/listinfo/piclist > or, via email, send a message with subject or body 'help' to > piclist-request@mit.edu > > You can reach the person managing the list at > piclist-owner@mit.edu > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Piclist digest..." > > > Today's Topics: > > 1. Re: [OT] Light running backward? (Dave Lag) > 2. Re: [PIC] pickit 1 failure modes (Peter) > 3. Re: [OT] Photons (Peter) > 4. Re: [OT] PicList Traffic (Peter) > 5. Re: [OT] PicList Traffic (Gerhard Fiedler) > 6. RE: [PIC] pickit 1 failure modes (Steven Howes) > 7. Re: [EE] solenoids and power transistors (Darren Gibbs) > 8. Re: [EE] solenoids and power transistors (Olin Lathrop) > 9. Re: [EE] solenoids and power transistors (Darren Gibbs) > 10. RE: [AD] inventory of components (Jan-Erik Soderholm) > 11. Re: [EE] solenoids and power transistors (Darren Gibbs) > 12. Re: [EE] solenoids and power transistors (Darren Gibbs) > 13. Re: [EE] solenoids and power transistors (Spehro Pefhany) > 14. Re: [EE] solenoids and power transistors (Darren Gibbs) > 15. Re: [EE] solenoids and power transistors (Tom Sefranek) > 16. Re: [AD] inventory of components (Denny Esterline) > 17. RE: [AD] inventory of components (Jan-Erik Soderholm) > 18. [OT] pedia entries for specialists (Jinx) > 19. Re: [EE] solenoids and power transistors (Spehro Pefhany) > 20. Re: [OT] Who would you choose ? (Jinx) > 21. [OT] Library classification systems (Gerhard Fiedler) > 22. Re: [OT] Photons (Gerhard Fiedler) > 23. [OT] Top 10 Strangest Gadgets of the Future ( G?khan SEVER ) > 24. Re: RTOS alternatives for PIC18micro family ( G?khan SEVER ) > 25. [PIC] RTOS alternatives for PIC18micro family ( G?khan SEVER ) > 26. [PIC] Merging pins into a "virtual" port/register in CCS > (moja nona) > 27. Re: [EE] solenoids and power transistors (Olin Lathrop) > 28. Re: [EE] solenoids and power transistors (Olin Lathrop) > 29. RE: [PIC] pickit 1 failure modes (Phillip) > 30. RE: [PIC] pickit 1 failure modes (Phillip) > 31. Re: [PIC] Merging pins into a "virtual" port/register in CCS > (Johan Baarman) > 32. Re: [EE] solenoids and power transistors (Dave Tweed) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 27 May 2006 12:36:29 -0400 > From: Dave Lag > Subject: Re: [OT] Light running backward? > To: "Microcontroller discussion list - Public." > Message-ID: <4478800D.1030401@rogers.com> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Gerhard Fiedler wrote: >> Bill & Pookie wrote: >> >> >>>When I was in the stacks looking for books on chess,...... >> >>>Also at that time, considered the Dewey Decimal System to be universal. >> >> It's a bit more global than the World Series , but apparently not the >> only player in town outside the USA. See e.g. http://www.udcc.org/ >> >> Gerhard >> > > > Very interesting, had my wife take a quick look- seems to an > extension/standardization to the LC (Library of Congress)? > D > > > > ------------------------------ > > Message: 2 > Date: Sat, 27 May 2006 20:50:45 +0300 (IDT) > From: Peter > Subject: Re: [PIC] pickit 1 failure modes > To: "Microcontroller discussion list - Public." > Message-ID: > Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed > > > On Sat, 27 May 2006, William Chops Westfield wrote: > >> Is there a known failure mode for the pickit one where a 12F675 >> will fail to verify, even though it seems to work? This has been >> happening recently and I shrugged it off, but the resulting PICs >> have seemed to become "flakey" over time (or stop working entirely), >> and I'm wondering whether they were properly programmed in the >> first place. (unfortunately, the PICs are in an app where there >> are other reasons they might fail as well...) > > I had a 12C509JW die by static to MCLR. It became unreadable and > unwritable but continued to work until it failed 'by itself' much later. > The symptom was leakage between MCLR and Vss (about 50 ohms). This > appeared a week after the event. JWs are pricey. > > Peter > > > ------------------------------ > > Message: 3 > Date: Sat, 27 May 2006 20:52:33 +0300 (IDT) > From: Peter > Subject: Re: [OT] Photons > To: "Microcontroller discussion list - Public." > Message-ID: > Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed > > > > On Sat, 27 May 2006, Gerhard Fiedler wrote: > >> Peter wrote: >> >>>> Most of mathematics -- the language in which most physical theories >>>> are expressed -- has no metaphor that is grounded in reality as we >>>> know it (with our senses). >>> >>> Yeah, pity that geometry actually means 'earth measuring' in Greek. >> >> Did you agree ("yeah") or disagree ("pity", "'earth measuring'")? :) > > Parsing my phrase yields two sentences, the first one is 'Yeah' and the > second is the rest after the comma ... > > Peter > > > ------------------------------ > > Message: 4 > Date: Sat, 27 May 2006 20:54:37 +0300 (IDT) > From: Peter > Subject: Re: [OT] PicList Traffic > To: "Microcontroller discussion list - Public." > Message-ID: > Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed > > > > On Sat, 27 May 2006, Gerhard Fiedler wrote: > >> James Newton, Host wrote: >> >>> The only way to clear it is to stop and start the service or restart the >>> PC. The restart is easier, [...] >> >> Hm... Restarting the service can be done with scheduling "iisreset >> /restart" at a schedule of your convenience. Couldn't be much easier, I >> would think :) > > Why are you assuming the process would be responsive, from the op's > description of the problem (or is it a predicament) ? ;-) > > Peter > > > ------------------------------ > > Message: 5 > Date: Sat, 27 May 2006 17:00:58 -0300 > From: Gerhard Fiedler > Subject: Re: [OT] PicList Traffic > To: piclist@mit.edu > Message-ID: > Content-Type: text/plain; charset="us-ascii" > > Peter wrote: > >> On Sat, 27 May 2006, Gerhard Fiedler wrote: >> >>> James Newton, Host wrote: >>> >>>> The only way to clear it is to stop and start the service or restart >>>> the >>>> PC. The restart is easier, [...] >>> >>> Hm... Restarting the service can be done with scheduling "iisreset >>> /restart" at a schedule of your convenience. Couldn't be much easier, I >>> would think :) >> >> Why are you assuming the process would be responsive, from the op's >> description of the problem (or is it a predicament) ? ;-) > > Because he said that "to stop and start the service" solves his problem. > This effect can be achieved with this command (and of course in other > ways). > > Gerhard > > > > ------------------------------ > > Message: 6 > Date: Sat, 27 May 2006 21:15:32 +0100 > From: "Steven Howes" > Subject: RE: [PIC] pickit 1 failure modes > To: "Microcontroller discussion list - Public." > Message-ID: > Content-Type: text/plain; charset="iso-8859-1" > > I am afraid i have just *ahem* toasted my pickit2.. i dont think it had > the latest firmware on it because i had only just purchased it, after > destroying my last one... > > Steve > > > -----Original Message----- > From: piclist-bounces@mit.edu on behalf of Xiaofan Chen > Sent: Sat 5/27/2006 3:35 PM > To: Microcontroller discussion list - Public. > Subject: Re: [PIC] pickit 1 failure modes > > On 5/27/06, Steven Howes wrote: >> >> Yea i have noticed that you get verify failed with eeprom write on in the >> pickit 1 and 2. Always puts me on edge :S. > > I have not encountered verification failure since v1.12 with PICkit 2. Do > you have a test case? Thanks. > > Regards, > Xiaofan > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > -------------- next part -------------- > A non-text attachment was scrubbed... > Name: not available > Type: application/ms-tnef > Size: 2981 bytes > Desc: not available > Url : > http://mailman.mit.edu/mailman/private/piclist/attachments/20060527/52e4e2c8/attachment.bin > > ------------------------------ > > Message: 7 > Date: Sat, 27 May 2006 15:14:10 -0700 > From: Darren Gibbs > Subject: Re: [EE] solenoids and power transistors > To: "Microcontroller discussion list - Public." > Message-ID: > Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed > > > On May 27, 2006, at 7:10 AM, Russell McMahon wrote: > >> Nobody seems to have solved your 'latch on' conundrum. > > Thanks for asking, I'm still very curious about this. > >> You didn't provide quite enough information for us to be sure what >> you are doing. >> >> Can you provide a full circuit of the relevant portion OR describe it >> fully. > > I have a 1K resistor on the base, and have tried switching using the > PIC, and by hand -- touch wire to 5V, touch wire to Gnd. > > I have a surplus 50V 5A linear power supply (built like tank, > delightful 60Hz hum generator). +V is connected to solenoid, other > side of solenoid to the collector, emitter connected to Gnd. > > There is a snubber diode connecting the emitter back to the > collector. Which as I look at it is not literally in parallel with > the solenoid, but the book I got this from claims that this is > equivalent. > >> When you turn it off, how do you do it - do you ground the resistor >> input via PIC pin or float the driving pin. > > Tried with PIC, floating, and connecting to Gnd. > >> If you ground the input to the 1K resistor when the large solenoid is >> on, does it till stay on? > > yes > > darren > > > ------------------------------ > > Message: 8 > Date: Sat, 27 May 2006 18:46:29 -0400 > From: olin_piclist@embedinc.com (Olin Lathrop) > Subject: Re: [EE] solenoids and power transistors > To: "Microcontroller discussion list - Public." > Message-ID: <000701c681df$65a35190$0300a8c0@main> > Content-Type: text/plain; charset="iso-8859-1" > > Darren Gibbs wrote: > >> I have a surplus 50V 5A linear power supply (built like tank, >> delightful 60Hz hum generator). > > OK, but once again, how much current does the solenoid draw? > >> There is a snubber diode connecting the emitter back to the >> collector. > > That's not a snubber. It must be accross the relay coil. From emitter to > collector isn't doing an good. > > This is why we want to see the whole schematic, not just the parts you > think > are important and not your interpretation of it. > >> Which as I look at it is not literally in parallel with >> the solenoid, > > Right. > >> but the book I got this from claims that this is >> equivalent. > > That's nonsense. Think about it. How is a diode from the bottom of the > relay to ground going to catch the solenoid current when the transistor > turns off? > > > ****************************************************************** > Embed Inc, Littleton Massachusetts, (978) 742-9014. #1 PIC > consultant in 2004 program year. http://www.embedinc.com/products > > > ------------------------------ > > Message: 9 > Date: Sat, 27 May 2006 16:04:49 -0700 > From: Darren Gibbs > Subject: Re: [EE] solenoids and power transistors > To: "Microcontroller discussion list - Public." > Message-ID: <9CBF8C09-393C-4BA3-B6C8-9000B69E51DF@yahoo.com> > Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed > > > On May 26, 2006, at 11:11 AM, Olin Lathrop wrote: >>> Small-Signal Current Gain Ic = 3A, Ie = 4V, f=1MHz >>> (not sure if this is what you mean by gain specs) >> >> That shows the parameters at which they were going to give you the >> gain, but >> not the gain itself. That is probably on the next line, which you >> didn't >> show. Also, 4V doesn't make sense for Ie. You probably didn't copy >> something correctly. > > Proofreading is always helpful: Ic = 3A, VCE = 4V, f = 1MHz > > At the top of the data sheet there is: > > High DC Current Gain: hFE = 2500 typ @ Ic = 4A > >> In any case, I was trying to see if your transistor was being given >> enough >> base drive. How much current do the relays draw at your maximum >> supply >> voltage? For starters until you can report the real current gain, >> figure >> such a power transistor needs a base current of 1/15 the maximum >> collector >> current. If your relays draw 5A, then that means you need 335mA of >> base >> current. > > So after some time with the circuit and a meter here's what I measure: > > This time using a 24V, 1.7A power supply. > > When engaged the current through the solenoid (Ice, if I understand > the nomenclature correctly) is 1.2A. Vce is 5.5V. The Base to > Emitter current when engaged is 17mA, which seems very low. > Grounding the base doesn't change CE voltage or current. > >> lso note the power dissipation. Even at Vce of 500mV that is >> still 2.5W. A free standing TO-220 isn't going to take that for >> long, and >> Vce is likely between 1V and 1.5V at maximum current. > > For the purposes of the actual project, I'm just hitting things with > the solenoids, so I'm sending 1ms - 10ms pulses. > > thanks for your help, > > darren > > > ------------------------------ > > Message: 10 > Date: Sun, 28 May 2006 01:17:31 +0200 (MEST) > From: Jan-Erik Soderholm > Subject: RE: [AD] inventory of components > To: piclist@mit.edu > Message-ID: <3322701.1148771851275.JavaMail.tomcat@pne-ps3-sn1> > Content-Type: text/plain;charset="ISO-8859-1" > > Vasile Surducan wrote : > >> ... if it's a seriuos offer (milions of parts) as you said. > > I got a list by mail. > > There are > 1.1 millons of just one part (a red standard LED). > And over 2.7 milions (185 reels) of a 68 pF cer chip smd cap. > And 150.000 1N4007 diods. > > Doesn't look as some hobbyists "don't need" stuff... :-) > > Regards, > Jan-Erik. > > > > > > ------------------------------ > > Message: 11 > Date: Sat, 27 May 2006 16:20:23 -0700 > From: Darren Gibbs > Subject: Re: [EE] solenoids and power transistors > To: "Microcontroller discussion list - Public." > Message-ID: > Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed > > > On May 27, 2006, at 3:46 PM, Olin Lathrop wrote: >>> but the book I got this from claims that this is >>> equivalent. >> >> That's nonsense. Think about it. How is a diode from the bottom >> of the >> relay to ground going to catch the solenoid current when the >> transistor >> turns off? > > It seemed odd to me certainly. My thought was that it was something > too clever for my newbie level of understanding to make sense of, so > I just transcribed it literally from the book. > > Thanks again for helping me through this, > > darren > > > ------------------------------ > > Message: 12 > Date: Sat, 27 May 2006 16:37:16 -0700 > From: Darren Gibbs > Subject: Re: [EE] solenoids and power transistors > To: "Microcontroller discussion list - Public." > Message-ID: > Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed > > So the answer appears to be the diode. When it's in parallel with > the transistor as the book shows, it causes the latching behavior. > When I put the diode in parallel with the solenoid, no more latching. > > So now I know what's wrong, but not why it does what it does. Can > anyone explain why the transistor would stay on because of a path for > current to get from E back to C? > > mystery half solved, > > darren > > > > ------------------------------ > > Message: 13 > Date: Sat, 27 May 2006 19:48:37 -0400 > From: Spehro Pefhany > Subject: Re: [EE] solenoids and power transistors > To: "Microcontroller discussion list - Public." > Message-ID: <5.1.1.5.2.20060527193927.0400a458@mail.interlog.com> > Content-Type: text/plain; charset="us-ascii"; format=flowed > > At 04:20 PM 5/27/2006 -0700, you wrote: > >>On May 27, 2006, at 3:46 PM, Olin Lathrop wrote: >> >> but the book I got this from claims that this is >> >> equivalent. >> > >> > That's nonsense. Think about it. How is a diode from the bottom >> > of the >> > relay to ground going to catch the solenoid current when the >> > transistor >> > turns off? >> >>It seemed odd to me certainly. My thought was that it was something >>too clever for my newbie level of understanding to make sense of, so >>I just transcribed it literally from the book. > > The collector junction was avalanching and absorbing perhaps half of the > total energy stored in the coil. > >>Thanks again for helping me through this, > > You can swap out the diode, in the current position, for a TVS or beefy > zener, and the circuit will work as-is. For example, a 1.5KE62A (JEDEC > 1N6290A) . The solenoid will drop out faster than if you used a (cheaper) > 1N400x across the coil. > If you don't care about the drop-out time, the 1N400x is easier on both > the transistor and the diode. > >>Best regards, > > Spehro Pefhany --"it's the network..." "The Journey is the > reward" > speff@interlog.com Info for manufacturers: > http://www.trexon.com > Embedded software/hardware/analog Info for designers: > http://www.speff.com > ->>Test equipment, parts OLED displys > http://search.ebay.com/_W0QQsassZspeff > > > > > ------------------------------ > > Message: 14 > Date: Sat, 27 May 2006 17:04:09 -0700 > From: Darren Gibbs > Subject: Re: [EE] solenoids and power transistors > To: "Microcontroller discussion list - Public." > Message-ID: <43ACD06C-2620-4AC0-9994-1CD908B75F98@yahoo.com> > Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed > > > On May 27, 2006, at 4:48 PM, Spehro Pefhany wrote: >> You can swap out the diode, in the current position, for a TVS or >> beefy >> zener, and the circuit will work as-is. For example, a 1.5KE62A (JEDEC >> 1N6290A) . The solenoid will drop out faster than if you used a >> (cheaper) >> 1N400x across the coil. > > Cool... I'll check into that as well. > >> If you don't care about the drop-out time, the 1N400x is easier on >> both the transistor and the diode. > > So is it smart in this circumstance to have something on both the > transistor and the diode? Or have I misunderstood? > > darren > > > ------------------------------ > > Message: 15 > Date: Sat, 27 May 2006 20:06:09 -0400 > From: Tom Sefranek > Subject: Re: [EE] solenoids and power transistors > To: "Microcontroller discussion list - Public." > Message-ID: <4478E971.3070807@cmcorp.com> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > > > Darren Gibbs wrote: > >>So the answer appears to be the diode. When it's in parallel with >>the transistor as the book shows, it causes the latching behavior. >>When I put the diode in parallel with the solenoid, no more latching. >> >>So now I know what's wrong, but not why it does what it does. Can >>anyone explain why the transistor would stay on because of a path for >>current to get from E back to C? >> > First things first, You HAVE to provide a inductive dump path for the > energy stored in the coil! > Think of it as a current flywheel, you get the current flowing in the > coil to cause the solenoid action. > When you turn off the current source, the stored magnetic field MUST > collapse and the coil becomes > a generator. (With potentially a VERY high voltage compliance!) > The generated current is equal to the applied current , and it WILL find > a place to go! > In your case, It found your Collector Base junction, as the voltage VERY > rapidly climbed as the transistor turned > off, causing an avalanche. So then it finds the Base Emitter junction > turning the transistor ON, vola! latchup. > > Put the diode across the LOAD (like you old me!) and it will supply a > path for the load dump current. > >> >>mystery half solved, >> >>darren >> >> >> > > -- > * > | __O Thomas C. Sefranek WA1RHP@ARRL.net > |_-\<,_ Amateur Radio Operator: WA1RHP > (*)/ (*) Bicycle mobile on 145.41, 448.625 MHz > > http://hamradio.cmcorp.com/inventory/Inventory.html > http://www.harvardrepeater.org > > > > > ------------------------------ > > Message: 16 > Date: Sat, 27 May 2006 20:07:32 -0400 > From: "Denny Esterline" > Subject: Re: [AD] inventory of components > To: "Microcontroller discussion list - Public." > Message-ID: <001701c681ea$b94d0240$9a401545@me> > Content-Type: text/plain; charset="iso-8859-1" > >> >> There are > 1.1 millons of just one part (a red standard LED). > > Prices? > > -Denny > > > > > ------------------------------ > > Message: 17 > Date: Sun, 28 May 2006 02:30:21 +0200 (MEST) > From: Jan-Erik Soderholm > Subject: RE: [AD] inventory of components > To: piclist@mit.edu > Message-ID: <1952522.1148776221733.JavaMail.root@pne-ps2-sn1> > Content-Type: text/plain;charset="ISO-8859-1" > > Denny Esterline wrote : > >> Prices? > > Nothing but a general statement saying > "half of Digikey". > > Which I think is rather high without > a known background for the batch... > > Jan-Erik. > > > > > > ------------------------------ > > Message: 18 > Date: Sun, 28 May 2006 12:41:36 +1200 > From: Jinx > Subject: [OT] pedia entries for specialists > To: pic microcontroller discussion list > Message-ID: <006801c681ef$7bc4a6d0$0100a8c0@ivp2000> > Content-Type: text/plain; charset=iso-8859-1 > > http://uncyclopedia.org/wiki/Morse_code > > http://uncyclopedia.org/wiki/Binary > > http://uncyclopedia.org/wiki/Braille > > http://uncyclopedia.org/wiki/ROT13 > > > > ------------------------------ > > Message: 19 > Date: Sat, 27 May 2006 21:21:25 -0400 > From: Spehro Pefhany > Subject: Re: [EE] solenoids and power transistors > To: "Microcontroller discussion list - Public." > Message-ID: <5.1.1.5.2.20060527203200.04002800@mail.interlog.com> > Content-Type: text/plain; charset="us-ascii"; format=flowed > > At 05:04 PM 5/27/2006 -0700, you wrote: > >>On May 27, 2006, at 4:48 PM, Spehro Pefhany wrote: >> > You can swap out the diode, in the current position, for a TVS or >> > beefy >> > zener, and the circuit will work as-is. For example, a 1.5KE62A (JEDEC >> > 1N6290A) . The solenoid will drop out faster than if you used a >> > (cheaper) >> > 1N400x across the coil. >> >>Cool... I'll check into that as well. >> >> > If you don't care about the drop-out time, the 1N400x is easier on >> > both the transistor and the diode. >> >>So is it smart in this circumstance to have something on both the >>transistor and the diode? Or have I misunderstood? > > Okay, you can think of these three being in series: > 1. the supply, generally with a fat output capacitor > 2. the transistor (on or off, with or without a TVS) > 3. the coil (with or without a diode) > > (view with fixed-width font such as Courier) > > Diode > +-----|<-----------+ > | | > | ___ | > o--------+----UUU- ---------|------------------------+ > | | | > | Solenoid | | > | 31R | C | > | .----------|------------------. | > | | | TIP122 | | > | | | | | > | | | | | > | | +------+-----+ | | > | + | | | | | | > ### | | | | | | > --- B | |/ | | | | > | |----+---| | | | | > | | | |> | | | | > 50VDC | | .-. | | | | | > | | | | | | | | | TVS > | | 8K| | | | | | | > | | '-' | | | | \ - \ > | | | | |/ - | ^ > | | +-----+----| ^ | / \ > | | .-. |> | | --- > | | | | | | | | > | | | | | | | | > | | '-' 120R | | | | > | | | | | | | > | | +------------+-----+ | | > | '-----------------|-----------' | > | E | | > | | | > o---------+-------------------------+-----------------+ 0V > > When the transistor switches off, the voltage at the collector rises from > about 0.8V typically (assuming forced beta of 250, so base current of > 6.4mA). If there is a diode across the coil, the voltage rises to a diode > drop above whatever the supply voltage is at the time, and that is your > maximum collector voltage. The current continues to flow at 1.6A > decreasing > exponentially toward zero, and most of the stored energy is dissipated in > the copper of the coil. If there is a TVS in there, it will not conduct > unless the supply voltage is higher than the TVS breakdown. BTW, the > 50V is a bit close to the 60V breakdown voltage for a TIP120, so a TIP122 > would be a better choice for the few pennies more you get 100V > breakdown and (unlike MOSFETs) no worse "on" characteristics. > > If there is no diode in there, the voltage rises to the TVS breakdown, > about 62V for the TVS I suggested. It's guaranteed to have less than > 85V across it with 18A current, so it will clamp the voltage nicely > for a TIP122. With that option, more of the energy is dissipated in > the TVS, and the magnetic field collapses more quickly so the solenoid > drops out faster. A higher voltage TVS (well within the ratings of the > transistor) will be even faster. > > The TVS also protects the transistor if there is a high voltage > transient on your power supply caused by something else in the circuit. > > Sometimes it's possible to use a low power C-B zener and cause the > transistor > to turn on partially and dissipate the power in the junction, but that's > much harder on the transistor and has other potential issues. > It's sometimes done in power ICs. Some MOSFETs are rated to safely absorb > a > certain amount of inductive energy through avalanche, but that tends to be > a rather small amount of energy compared to what an 80W solenoid stores. > > So, the diode or TVS would be the same whether you use a MOSFET or > darlington. > > At 50V (unregulated?) operating voltage and 1.6A there are not a huge > number > of logic-level MOSFETs with low Rds(on) and good voltage margin, so you > might > need to factor a 10V-12V gate drive circuit into the equation, but the > heatsink savings might be worth the extra cost and complexity. > >>Hope this helps, > > > Best regards, > > > Spehro Pefhany --"it's the network..." "The Journey is the > reward" > speff@interlog.com Info for manufacturers: > http://www.trexon.com > Embedded software/hardware/analog Info for designers: > http://www.speff.com > ->>Test equipment, parts OLED displys > http://search.ebay.com/_W0QQsassZspeff > > > > > ------------------------------ > > Message: 20 > Date: Sun, 28 May 2006 13:15:40 +1200 > From: Jinx > Subject: Re: [OT] Who would you choose ? > To: "Microcontroller discussion list - Public." > Message-ID: <007601c681f4$3de8d430$0100a8c0@ivp2000> > Content-Type: text/plain; charset=iso-8859-1 > >> One might well have assumed that "admire" and "like" (in this >> sense) were synonymous. But Jinx would have us consider >> otherwise. > > An example I could use is performers. I may like some artist, eg > a comedian or musician, on a personal level, but not admire them. > I might consider them a nice guy but material is weak or crap and > feel they're in the wrong business. So I don't admire them for > hanging around. OTOH I could admire them for stick-to-it-iveness. > In that regard, "admire" is not a suitable word > > "admire" is subject to the fickleness and personality and views of > the "admirer". There are so many qualities to take into account. As > an extreme example - Kim Jong-il. Speaking unemotionally, you > could admire how he unites North Korea. The way he does it ? Not > admirable (to Western eyes) > > "admire" is open to too much (mis)interpretation > > > > ------------------------------ > > Message: 21 > Date: Sat, 27 May 2006 23:05:58 -0300 > From: Gerhard Fiedler > Subject: [OT] Library classification systems > To: piclist@mit.edu > Message-ID: <10wwexzznira3$.1qjhzbuum71qc$.dlg@40tude.net> > Content-Type: text/plain; charset="us-ascii" > > Dave Lag wrote (in "Re: [OT] Light running backward?"): > >>>>Also at that time, considered the Dewey Decimal System to be universal. >>> >>> It's a bit more global than the World Series , but apparently not the >>> only player in town outside the USA. See e.g. http://www.udcc.org/ >> >> Very interesting, had my wife take a quick look- seems to an >> extension/standardization to the LC (Library of Congress)? > > Allright... now we have three common classification systems: > > - Dewey Decimal Classification (DDC, > http://en.wikipedia.org/wiki/Dewey_Decimal_Classification) > - Universal Decimal Classification (UDC, > http://en.wikipedia.org/wiki/Universal_Decimal_Classification) > - Library of Congress Classification (LCC, > http://en.wikipedia.org/wiki/Library_of_Congress_Classification) > > All were created apparently more or less in parallel and with more or less > cross-pollination in the last decades of the 19th century. UDC seems to be > the only one to classify relationships between different classes in one > item, and the number-based system that DDC and UDC use seems to be better > suited for computerized handling. > > Gerhard > > > > ------------------------------ > > Message: 22 > Date: Sat, 27 May 2006 23:20:15 -0300 > From: Gerhard Fiedler > Subject: Re: [OT] Photons > To: piclist@mit.edu > Message-ID: > Content-Type: text/plain; charset="us-ascii" > > Peter wrote: > >> On Sat, 27 May 2006, Gerhard Fiedler wrote: >> >>> Peter wrote: >>> >>>>> Most of mathematics -- the language in which most physical theories >>>>> are expressed -- has no metaphor that is grounded in reality as we >>>>> know it (with our senses). >>>> >>>> Yeah, pity that geometry actually means 'earth measuring' in Greek. >>> >>> Did you agree ("yeah") or disagree ("pity", "'earth measuring'")? :) >> >> Parsing my phrase yields two sentences, the first one is 'Yeah' and the >> second is the rest after the comma ... > > /Everything/ started in reality, somewhen, somewhere... :) > > Gerhard > > > > ------------------------------ > > Message: 23 > Date: Sun, 28 May 2006 07:50:57 +0300 > From: " G?khan SEVER " > Subject: [OT] Top 10 Strangest Gadgets of the Future > To: "Microcontroller discussion list - Public." > Message-ID: > <608fd9de0605272150i167a0802g6bb745d6e3c79f5e@mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Goodmorning, > > http://www.techeblog.com/index.php/tech-gadget/top-10-strangest-gadgets-of-the-future > > Gadgets are everywhere.. > > My definite favourite is VirtuSphere on the list. I would like to spend my > whole Sunday in it :) > > Source : Slashdot. > > G?khan SEVER. > > > ------------------------------ > > Message: 24 > Date: Sun, 28 May 2006 08:11:32 +0300 > From: " G?khan SEVER " > Subject: Re: RTOS alternatives for PIC18micro family > To: "Microcontroller discussion list - Public." > Message-ID: > <608fd9de0605272211u7dc4b652m50bd1c4a04b6dedf@mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Thank you very much for your guidelines. > > I hankered after Pumkin Salvo (http://www.pumpkininc.com/) which has huge > support for Microchip's devices. PIC12|14000|16|17|18 *PICmicro*(r) MCUs > and > also for *PIC24* MCUs and *dsPIC*(r) DSCs. Besides its ported other mcus > as > well. Lots application notes and programming examples are very significant > on the view point of novice programmer. Restricted-demo version can be > downloaded from that page. > > The most ported RTOS should be Micrium's. Huge range of mcu list.. > MicroC/OS-II, > The Real-Time > Kernelbook > is very outstanding but i dont think its a good starting point for the > starter rtos app developer. > > Although Salvo can be good candidate for me to get started on that topic, > the full version's price way over my budget. If i can find some help i > will > stick to free alternatives. > > Again thanks, > G?khan SEVER. > > > On 5/27/06, Xiaofan Chen wrote: >> >> On 5/27/06, G?khan SEVER wrote: >> > Goodafternoon all, >> > >> > I've seen some different OS ports for PIC18. But not sure which one is >> more >> > effecitve and less painfull to design. >> > >> > SalvoRTOS, PIC18OS, FreeRTOS, uC/OS-II for PIC18.. >> > >> > Whats your comments on that? >> > >> >> I guess none of them are really useful for hobbyist project. >> >> PIC18OS and FreeRTOS are free and open source so I think they might >> be worth studying. >> >> Regards, >> Xiaofan >> >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > > > ------------------------------ > > Message: 25 > Date: Sun, 28 May 2006 08:24:19 +0300 > From: " G?khan SEVER " > Subject: [PIC] RTOS alternatives for PIC18micro family > To: "Microcontroller discussion list - Public." > Message-ID: > <608fd9de0605272224ya444df4i1fc8fdf0a743f0e0@mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > I had forgotten to add proper tag to my posting. Apologies for that.. > > Here is my original mail: > > Goodafternoon all, // Now is morning in here :) > > I've seen some different OS ports for PIC18. But not sure which one is > more > effecitve and less painfull to design. > > SalvoRTOS, PIC18OS, FreeRTOS, uC/OS-II for PIC18.. > > Whats your comments on that? > > Thanks, > G?khan SEVER. > > > //------------------------------------------------------------------------------------------------------------------- > > Xiaofan Chen replied after some time: > > > I guess none of them are really useful for hobbyist project. > > PIC18OS and FreeRTOS are free and open source so I think they might > be worth studying. > > Regards, > Xiaofan > > //------------------------------------------------------------------------------------------------------------------- > > And i've replied and realized that i've forgotten to add the tag ;( > > > Thank you very much for your guidelines. > > I hankered after Pumkin Salvo (http://www.pumpkininc.com/) which has huge > support for Microchip's devices. PIC12|14000|16|17|18 *PICmicro*(r) MCUs > and > also for *PIC24* MCUs and *dsPIC*(r) DSCs. Besides its ported other mcus > as > well. Lots application notes and programming examples are very significant > on the view point of novice programmer. Restricted-demo version can be > downloaded from that page. > > The most ported RTOS should be Micrium's. Huge range of mcu list.. > MicroC/OS-II, > The Real-Time > Kernelbook > is very outstanding but i dont think its a good starting point for the > starter rtos app developer. > > Although Salvo can be good candidate for me to get started on that topic, > the full version's price way over my budget. If i can find some help i > will > stick to free alternatives. > > Again thanks, > G?khan SEVER. > > > //-------------------------------------------------------------------------------------------------------------------- > > > ------------------------------ > > Message: 26 > Date: Sun, 28 May 2006 10:45:21 +0200 > From: "moja nona" > Subject: [PIC] Merging pins into a "virtual" port/register in CCS > To: > Message-ID: <005d01c68233$0f77cbd0$1f840599@mriggy> > Content-Type: text/plain; charset="iso-8859-1" > > Hello. > > Situation: Driving a LCD. 3 pins are say on PORTA, 4 pins are on PORTB. > I am using CCS for programing. Is there a way to group the pins of both > the ports into a single register? The code would be easyer/prettyer. > > Regards! > > > ------------------------------ > > Message: 27 > Date: Sun, 28 May 2006 08:55:04 -0400 > From: olin_piclist@embedinc.com (Olin Lathrop) > Subject: Re: [EE] solenoids and power transistors > To: "Microcontroller discussion list - Public." > Message-ID: <001301c68255$f0ea0f20$0300a8c0@main> > Content-Type: text/plain; charset="iso-8859-1" > > Darren Gibbs wrote: >> So the answer appears to be the diode. When it's in parallel with >> the transistor as the book shows, it causes the latching behavior. >> When I put the diode in parallel with the solenoid, no more latching. >> >> So now I know what's wrong, but not why it does what it does. Can >> anyone explain why the transistor would stay on because of a path for >> current to get from E back to C? > > It stays on because the 1000 volts or so the solenoid produced when you > tried to turn off the transistor was rather beyond maximum ratings. > Anything the transistor does after that should not be a surprise. It has > nothing to do with the E-B diode. That diode was essentially not there. > > > ****************************************************************** > Embed Inc, Littleton Massachusetts, (978) 742-9014. #1 PIC > consultant in 2004 program year. http://www.embedinc.com/products > > > ------------------------------ > > Message: 28 > Date: Sun, 28 May 2006 09:06:56 -0400 > From: olin_piclist@embedinc.com (Olin Lathrop) > Subject: Re: [EE] solenoids and power transistors > To: "Microcontroller discussion list - Public." > Message-ID: <002401c68257$99836a90$0300a8c0@main> > Content-Type: text/plain; charset="iso-8859-1" > >> On May 27, 2006, at 4:48 PM, Spehro Pefhany wrote: >> You can swap out the diode, in the current position, for a TVS or >> beefy zener, and the circuit will work as-is. > > Yes, that should protect the transistor, but I still think that's the > wrong > place to deal with the relay load dump. The relay dump current now has to > go from the relay, thru the bottom lead, thru the TVS, thru the power > supply, and then back to the relay. The voltages at the transistor should > be safe, but there will still be large voltage spikes elsewhere. > > There should be something at least to deal with the high frequencies right > at the relay. A cap accross the relay will limit dV/dt so that other > components can handle the spikes better and to reduce RF emissions. Then > a > reverse diode to catch the current. If that causes the relay to turn off > too slowly, put a resistor in series with the diode, but make sure the > transistor is rated for the supply voltage plus the relay current times > the > transistor. > > > ****************************************************************** > Embed Inc, Littleton Massachusetts, (978) 742-9014. #1 PIC > consultant in 2004 program year. http://www.embedinc.com/products > > > ------------------------------ > > Message: 29 > Date: Sun, 28 May 2006 07:33:59 -0600 > From: "Phillip" > Subject: RE: [PIC] pickit 1 failure modes > To: "'Microcontroller discussion list - Public.'" > Message-ID: <003101c6825b$60afb300$0300a8c0@mygpssource.net> > Content-Type: text/plain; charset="us-ascii" > > Hi Bill > I'm using 16F676 and I failure to verify if I let the ICD2 choose the > memory > locations. > If I set it to manual and choose the full program range it works fine. > I'm not sure what is going on but apparently the ICD2 is programming less > memory than it is checking or that needs to be programmed. > > > > > > Phillip > Things should be as simple as possible but no simpler > > > > Phillip Coiner > CTO, GPS Source, Inc. > > > Your source for quality GNSS Networking Solutions and Design Services, > Now! > -----Original Message----- > From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf > Of > William Chops Westfield > Sent: Saturday, May 27, 2006 2:33 AM > To: Microcontroller discussion list - Public. > Subject: [PIC] pickit 1 failure modes > > Is there a known failure mode for the pickit one where a 12F675 > will fail to verify, even though it seems to work? This has been > happening recently and I shrugged it off, but the resulting PICs > have seemed to become "flakey" over time (or stop working entirely), > and I'm wondering whether they were properly programmed in the > first place. (unfortunately, the PICs are in an app where there > are other reasons they might fail as well...) > > BillW > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > > > ------------------------------ > > Message: 30 > Date: Sun, 28 May 2006 07:44:32 -0600 > From: "Phillip" > Subject: RE: [PIC] pickit 1 failure modes > To: "'Microcontroller discussion list - Public.'" > Message-ID: <003201c6825c$da8a59e0$0300a8c0@mygpssource.net> > Content-Type: text/plain; charset="us-ascii" > > I failure to verify > > Should read when I get a failure to verify > > > > > > Phillip > Things should be as simple as possible but no simpler > > > > Phillip Coiner > CTO, GPS Source, Inc. > > > Your source for quality GNSS Networking Solutions and Design Services, > Now! > > -----Original Message----- > From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf > Of > Phillip > Sent: Sunday, May 28, 2006 7:34 AM > To: 'Microcontroller discussion list - Public.' > Subject: RE: [PIC] pickit 1 failure modes > > Hi Bill > I'm using 16F676 and I failure to verify if I let the ICD2 choose the > memory > locations. > If I set it to manual and choose the full program range it works fine. > I'm not sure what is going on but apparently the ICD2 is programming less > memory than it is checking or that needs to be programmed. > > > > > > Phillip > Things should be as simple as possible but no simpler > > > > Phillip Coiner > CTO, GPS Source, Inc. > > > Your source for quality GNSS Networking Solutions and Design Services, > Now! > -----Original Message----- > From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf > Of > William Chops Westfield > Sent: Saturday, May 27, 2006 2:33 AM > To: Microcontroller discussion list - Public. > Subject: [PIC] pickit 1 failure modes > > Is there a known failure mode for the pickit one where a 12F675 > will fail to verify, even though it seems to work? This has been > happening recently and I shrugged it off, but the resulting PICs > have seemed to become "flakey" over time (or stop working entirely), > and I'm wondering whether they were properly programmed in the > first place. (unfortunately, the PICs are in an app where there > are other reasons they might fail as well...) > > BillW > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > > > ------------------------------ > > Message: 31 > Date: Sun, 28 May 2006 17:36:10 +0300 > From: Johan Baarman > Subject: Re: [PIC] Merging pins into a "virtual" port/register in CCS > To: "Microcontroller discussion list - Public." > Message-ID: <4479B55A.1070109@iki.fi> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Hi. > You might want to use this modified lcd driver found on ccs userforum. I > havent tested it myself, but it seems to be what you are looking for. > > http://www.ccsinfo.com/forum/viewtopic.php?t=24661 > > /Johan > > moja nona skrev: >> Hello. >> >> Situation: Driving a LCD. 3 pins are say on PORTA, 4 pins are on >> PORTB. I am using CCS for programing. Is there a way to group the pins of >> both the ports into a single register? The code would be easyer/prettyer. >> >> Regards! >> > > > > ------------------------------ > > Message: 32 > Date: Sun, 28 May 2006 10:49:37 -0400 > From: Dave Tweed > Subject: Re: [EE] solenoids and power transistors > To: > Message-ID: > Content-Type: text/plain; charset="us-ascii" > > olin_piclist@embedinc.com (Olin Lathrop) wrote: >> On May 27, 2006, at 4:48 PM, Spehro Pefhany wrote: >> > You can swap out the diode, in the current position, for a TVS or >> > beefy zener, and the circuit will work as-is. >> >> Yes, that should protect the transistor, but I still think that's the >> wrong place to deal with the relay load dump. The relay dump current now >> has to go from the relay, thru the bottom lead, thru the TVS, thru the >> power supply, and then back to the relay. The voltages at the transistor >> should be safe, but there will still be large voltage spikes elsewhere. > > Where? The power supply is fine -- you're not trying to back-drive it -- > the decaying current is still flowing in the "normal" direction from its > point of view. > > If you're trying to get the current to decay quickly in order to minimize > the hold time of the relay/solenoid (and the OP eventually said that he > wants "short pulses"), this is exactly the correct approach. > > Just pick a TVS/zener that has a rating 2x to 3x the supply voltage, and > pick a transistor that has a Vce rating with a comfortable margin above > that. For example, with a 50 V supply, use a 150 to 200 V TVS and a > transistor rated at 300 V. > > When the transistor cuts off, the collector will immediately* rise to the > TVS voltage and the coil current will drop rapidly. When the TVS stops > conducting, you'll see some self-resonant "ringing" of the coil at the > transistor collector, but this won't go above the TVS voltage, and the > negative peaks will be clamped by forward conduction of the TVS.** > > Pay attention to the average dissipation in the TVS -- calculate the > amount of energy dumped into it each time you switch off the transistor, > multiply this by the number of times per second you want to do this, and > make sure the total doesn't exceed the power rating of the device. > >> There should be something at least to deal with the high frequencies >> right at the relay. A cap accross the relay will limit dV/dt so that >> other components can handle the spikes better and to reduce RF emissions. > > Possibly. In most cases, the self-resonant frequency of the coil isn't > all that high to begin with. If you make the capacitor too large, then > the transistor needs to be able to handle the spike current of charging > it at turn-on, and this can be another source of RFI. > >> Then a reverse diode to catch the current. If that causes the relay to >> turn off too slowly, put a resistor in series with the diode, but make >> sure the transistor is rated for the supply voltage plus the relay >> current times the transistor. > > That last word should be "resistance". > > Yes, that works too, but for a given back voltage, the resistor will > still have a slower dropout (exponentially decaying voltage) than the > TVS approach (constant voltage). > > -- Dave Tweed > > * Actually, a half-cycle of the self-resonant frequency of the coil. > > ** This is the only time the power supply gets back-driven, but by > this point, the energy involved is miniscule. > > > ------------------------------ > > -- > http://www.piclist.com > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > > End of Piclist Digest, Vol 22, Issue 33 > *************************************** -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist