Post by thread:TOO DIFFICULT TO DECIDE: please help

<x-flowed>Hello to everybody. I'm a newcomer to PIC programming and I'm seeking for advice. I've been programming embedded systems in medical products under 6502, Z80, 68000, 68332 and just recently I'm getting back to it. I'm somewhat confused after some days of searching through the web for a micro that would fit my application, Tickit, PIC, TIGER and so on. Let me try to explain what I need and see if any of you guys can help. My application requires the following: - 8 channel serial ADC 8-10 bits (MAX186, MAX192 ??) with about 2 KHz sampling rate - 12-16 bit general I/O - RS232 serial communication - LCD 2 x 24 characters (serial, I2C, 8 bit bus ???) - Possibility of reprogramming the software without extracting any chip (RS232, other serial communication ??) - MIDI communication (31.25 K, is that possible on PICs ?) - PIC CPU (which model??) - Battery operated Development system: - C compiler (CCS ??) Do I need a startup kit or you advice to start from scratch with a prototyping board? Any self made project? I would hate to burn software with a programmer before trying software changes. I was convinced on PICs mainly because of the quality of the PICLIST web site. Thanks to all of you for sharing your work. Gianni ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com </x-flowed>

Gianni Freiles wrote: > > Hello to everybody. > I'm a newcomer to PIC programming and I'm seeking for advice. > I've been programming embedded systems in medical products under 6502, Z80, > 68000, 68332 and just recently I'm getting back to it. > I'm somewhat confused after some days of searching through the web for a > micro that would fit my application, Tickit, PIC, TIGER and so on. > > Let me try to explain what I need and see if any of you guys can help. > > My application requires the following: sounds very close to the dt106 pcb http://www.dontronics.com/dt106.html a good start i would think. Don McKenzie spam_OUTdonTakeThisOuTdontronics.com http://www.dontronics.com World's Largest Range of Atmel/AVR and PICmicro Hardware and Software. Free Basic Compiler and Programmer http://www.dontronics.com/runavr.html

Well you can ceertainly do pics or scenix (A pic clone). The scenix is my current favorite. Its a flash based, and offers a high-clock rate. 100Mhz. Programming is in circuit, along with debug. The question always comes down to cost/perfomance/ease of development. Pic arch. is very powerful for the pricepoint, but sounds like your application would be better served by multiple pics if thats the choice, there so cheap its no big deal. That way you can put a part for each thing your interface, and communicate with i2c. Currently doing a "droplett" server, on a simm, its a scenix part with 2+ Megabytes of flash and a ethernet connection. It will have a spare scenix part for pio connection. Just add the RJ45 jack. So shows the power. But you have to get used to coding "small". I'll look at the 16F877, the question always is code size, and how tight you code. My question would be how big is the MIDI data, and the data analysis functions. Sounds like your doing a bio-feedback device, and may need to look at a second of data per channel, that eats ram likes its going out of style. So its really, how much ram you need that drives, and how fast do you need to access it. pics usually have very limited ram directly accessable, 512 bytes to 1024, some parts are as small as 128bytes (Notice there is no K in that). So you have to think small. I've done lots of projects with pics and you can do thinks you never thought possible in very small sizes but you have to think about it first. Nothing worst than running out of memory before you start. At 03:59 PM 2/9/00 -0800, you wrote: >Do I hear a vote for the 16F877????? >Excepting the MIDI, I'm just about postive you can >do all of that stuff. With the built in ADC, FLASH >and extra I/O I know I could probably get his job >done. Maybe better (quicker) in ASM. But with >the ICD and it's prototype board (US $159 total,) >it would get him down the road fast. >Walt > >{Original Message removed}

This looks like a lot for a single PIC to do. Of course, you can use external buffers, etc. Or you can use multiple PIC's, but those flash parts are still pretty expensive to be using more than one. I'd look at Hitachi. They've got some really nice flash parts available now, with all the I/O you need, huge flash and RAM (compared to PIC's) and plenty of processing power including lots of 16-bit registers, multiple 16-bit timers and UARTs, 8-channel A/D's, and hardware multiply and divide. Demo boards run $99-$199, and include the universal in-circuit programmer which covers all their parts. I'm told some of the new parts are under $5.00. Be careful when you choose a particular part. Prices for nearly identical parts can be quite different, and some are quite expensive. The drawback is their tools are pricey. Their in-circuit-debugger is way better than Microchip's (it includes trace), but then it better be, because the price is over $1000. C-compiler is also in the same range, but is also excellent. I think their full emulator is around $6000, unless you're using their 32-bit processors (as do most Windows CE machines) and you need the emulator that's $15,000+. I've also used a Tiny-Tiger. For the price, it is an excellent product. Learning curve was about 2 days, coding with their Basic was easy, and the developers were available for tech support on phone and e-mail. By now, I expect that each of mine has tested about 50,000 production boards with nary a glitch. Drawback there is high unit cost. Just didn't want your job to be too easy (;-) Don