Oops - this was meant to be in reply to Spehro. ----- Original Message ----- From: "James Nick Sears" To: Sent: Friday, January 09, 2004 7:21 PM Subject: Re: [PICLIST] [PIC:] RS232 Driver IC Supply Noise > What is the proper way to do this? It seems that if you set the PORT value > high before setting the TRIS to output that it will get overwritten by the > pin value and if you set the TRIS to output first that the PIC will briefly > try to pull the pin low before taking it high. > > Thanks > Nick > > > ----- Original Message ----- > From: "Reelf Monsees" > To: > Sent: Friday, January 09, 2004 2:15 AM > Subject: Re: [PICLIST] [PIC:] RS232 Driver IC Supply Noise > > > Well, had the same problem with the max3221, it produced so much noise > that AD-sampling on the same board was impossible. No, decoupling etc. > was alright, just in case you might ask ... > The only solution was to switch the max3221 off while the ADC are > active. > > regards, > Reelf > > "Jan-Erik Soderholm XA (TN/PAC)" schrieb: > > > > James Nick Sears wrote : > > > > > I replaced the max3221 and the supply is still noisy as all > > > hell but the false !INVALID signals are not occurring. > > > Probably if I add some extra capacitance now I'll be ok > > > > Perhaps you should have put a "driver" between the PIC pin > > and the power supply of the MAX chip. Everything looks like > > the MAX has a varying current drain depending on what it's > > currently "doing". If it's feeding current out on the RS232 > > line, the charge pump have to work a little harder for a > > short while. Or put something like 100uf as a reservoar > > that is charged through current limiting resistor of around > > 200 ohms from the PIC pin. Or put a simple FET in between > > and switch the MAX chip directly to 5V. Or an ULN type of > > driver chip. > > > > > > > > By the way, I think I first heard about it on this list but > > > if anyone hasn't tried Chipquik removal solder yet it is > > > great stuff. I paid $18.50 for my kit and it has already > > > paid for itself several times over and I probably haven't > > > used 5% of it. > > > > Any URL that shows what this is ? > > > > Regards > > Jan-Erik. > > > > -- > > http://www.piclist.com hint: The PICList is archived three different > > ways. See http://www.piclist.com/#archives for details. > > -- > SyWiTec * Systeme f|r Wissenschaft und Technik > Bamberg & Monsees GbR > Steindamm 22 * D-28719 Bremen > Fon +49-421-646775 * Fax +49-421-646785 > http://www.sywitec.de/ > > > SmartKit Electronic - Der Online-Shop > http://www.smartkit.de/ > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.