On Fri, Nov 12, 2004 at 10:19:35AM -0500, John J. McDonough wrote: > ----- Original Message ----- > From: "Byron A Jeff" > Subject: Re: [PIC:] Getting started with PIC's > > > > And this is where I believe the real problem lay and why we have to be > > really aggressive about dissuading new 84 designs, or even implementing > > existing 84 projects. But there's a documentation vacuum that's real > > difficult to fill. My wrap up is coming... > > I tend to agree with you here, but I'm not so sure that the answer is simply > more dox. Not just more docs, more meaningful docs. Something along the lines of Fr. McGahee's PICUART tutorial for each of the major PIC peripherals plus a couple on systems integration (i.e. the digital clock that reads external temps and has a serial interface to a PC), and interrupt handling. > > > Of course I'd throw in my obligatory bootloader plug, which completely > obviates > > the need for a "programmer" in any sense... > > Jawel, the bootloader is another of those things I'm not the biggest fan of. > ICSP is pretty darned simple. I won't go into it again as I've beat that horse to a pulp. I'll just leave it with the fact that all higher level systems are essentially bootloaded, so it must have some merit. > > > The 16F84 is fine for the 1-14 chapters that you have, which BTW I really > > appreciate and can point people to. > > Thank you. Glad you took the time to take a peek. Unfortunately, a LOT also > happens on the QRP-L reflector, whose archives aren't all that easy to > search. > > > But my concern is chapters 15-30, which are of course unwritten. > > Well, almost. Lesson 15 is in the hands of the web site maintainer, and I > have a draft of 16. Topics? > > > Onboard periperals are important because they give a set and forget > abstraction > > interface that greatly simplifies any work beyond the novice level. And > frankly > > the 16F84 simply cannot deliver on those issues. It becomes a detailed > > software problem. > > I think you are right. I don't plan to do a lot more lessons in this > particular course. We will cover using an LCD, using a DDS, maybe a > frequency counter, and probably tie some of these things together with a > keyer project. Admittedly, talking to a DDS involves a little bit-banging, > but I certainly don't advocate successive approximation A/D with a resistor > network when half the price buys you a 7 channel A/D. Or simply use onboard ADC. That's an example of the types of applications I'm talking about. > > I think the more involved topics cry out for another part. I'm not so sure > what part that is. As you point out, there is enormous inertia to stay with > the part you first learned. Personally, I think being parochial about any > part is not the best plan, especially where you have a wide range of parts > with a common software model and different selections of peripherals. But > we have gotten a lot of people over the inertia of grokking a little > assembler in the first place. While I doubt I can be 100% successful in > getting everyone to explore more possibilities, I think we can make > significant headway. Agreed. But by starting at the top of the food chain with a part and working your way into it will give a novice a comfort level. Let's talk about a really small byte (pun intended) on the 16F88: the nanowatt module. As soon as you get started you get a win because you don't have to wire up a crystal or a resonator. I find it's easier to start with everything there and explain it one section at a time, then to plateau and have to move to a different part. Again I'm strictly talking from a hobby or extremely low volume persepctive. In high volume commercial applications, you have to go in the opposite direction and start with the smallest part that may fit, then squeeze as tight as possible. > > I am seeing evidence that I'm getting through. Different students have > begun projects with the 628, 818, 88 and 877, so the barrier isn't absolute. > But I bet for every student playing with another chip, there are ten trying > to put too much stuff into an 84. Right. And the problem is that there isn't a really good F88, 18F, or 16F87X based tutorial to point to and say "Work from here." > > > So John, when folks like Wouter and I go "Sheesh, not the 16F84 AGAIN!" > we're > > looking at the late beginner/intermediate aspects of using the parts, the > > proverbial chapters 15-30 of your tutorial. > > Yes, like I said, I won't be buying any more 84's. But I viewed the > complexity of even the 628 as too much for the students I have. My > interaction with them has convinced me I was right. I have to admit, I am > not confident I can convince them that the huge range of chips offers > features they may want. The heavy lifting there, though, is for Elmer 161. > Who knows, maybe we can come up with a "son of PIC-EL" with a dsPIC or > something on it. I think for this particular audience, that offers some > interesting possibilities. But even a part like the 16F88 has some really > cool stuff. Really cool stuff. That's why I wrote a comparison page on it here: http://www.finitesite.com/d3jsys/16F88.html > > By the way, the response has been amazing. When we first talked about doing > the kit to go with the course, I was concerned that we wouldn't be able to > move the roughly 100 of the things needed to break even. After all, this is > a pretty small niche. I got more concerned as the PIC-EL design got more > complex and pushed the price point up. Well, we finally cut the kits off > after 700 (this is, after all, a club project and the volunteers are fried), > and there are plenty of folks looking for more, and a fair number of > students just hand wiring the experiments. There is a lot of hunger for > this information. Cool. I hope this gives you some thoughts for the v2 version. BAJ _______________________________________________ http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist