krimo

Greetings All,

Here is my first robot, a line following robot (black line). Its based on the Intel 8088 microprocessor and was built for a class I was taking at college. It has photo-interrupters for line detection and a pair of H-Bridges for motor control. I chose to fabricate the printed circuit boards rather than use wire wrap because I had access to an LPKF M60 circuit board plotter and I knew it would be more reliable as well.

The bulldozer platform was a Toys-R-Us wired RC control toy purchased for $20. If I recall the blade of the dozer was not controllable. I think I'll modify it over this Christmas so that it can be run by a Freescale (Motorola) MC9S08QE128 DEMOQE128 low-cost evaluation board I recently received for attending the Freescale Coldfire V1 Seminar. You can get the same evaluation board from PEmicro.com or any number of electronics distributors for $99.

Access

Intel 8088... I haven't seen one of those in 15 years. When was that built?

krimo

Yes, the 8088 is old as the hills. I believe we actually used an 80C88. I think I built it in 2004, I'll have to check my notes . The curricula at Cal State Long Beach had everyone using that processor for their junior level Microprocessor design course. They have since switched to a Philips 8051 variant, I think it was the P89V51RD2 and now they are using another 8051 device variant made by Atmel.

I'm assuming that the reason they force the students to use the 8088 is because you have to use support chips to access the lower 8-bits of the multiplexed address and data bus along with the bus decoding and interface duties you're required to implement. I guess it makes for a good introductory academic exercise in hardware and software development.

Yub, yub, cmdr!

I like the Atmel AVRs best personally

krimo

I haven't tried the Atmel AVR yet. Is there a "low-cost" evaluation/development kit offered/available that has an included compiler/assembler. And, if you want to upgrade the compiler that comes with the eval/dev kit is it expensive?

Currently I'm looking for a microcontroller that has lots (~40) GPIO lines and can produce pulse widths approaching (1/32.768MHz) or 30.5175 ns with an included 32-bit data bus. Unfortunately, I think I'm going to be forced to use an FPGA to make this happen because the high end microcontrollers have a feature set that seemingly is not oriented for control but for multimedia and internet applications and the compilers that support the high end devices are expensive.

I've also heard at a seminar that you don't want to use Assembly with ARM microcontrollers unless you're an expert.

Access

Last time I used it (about a year ago) all the tools you needed were free from Atmel. But, the timer-hardware PWM outputs are limited, the most servos I could ever control with a single chip was 2. I've made 2-channel car controllers with it but not much else.

An ARM is probably what you need, there are ARMs avaliable that have many PWM outputs I am told. Assembly language, yeah, it's pretty bad on an ARM, but this day and age, there are few cases where you need to touch that.

krimo

Thanks Access.

dknovick

I'm a PIC fanboy... (but I like Atmel's as well)

The nice thing about Atmel, is that you can use the gcc compiler: [link=http://winavr.sourceforge.net/]WINAVR[/link]
[link=http://www.sparkfun.com/commerce/categories.php]Sparkfun[/link] has a nice selection of programmers and eval. boards



Both Microchip and Atmel have 32 bit microcontrollers and lots of I/O. I'm not sure on the timing, but a quick look at their website, says PICs will run at 80MHz and the Atmels @ 66MHz

krimo

Thanks for the info. However, I believe Microchip and Atmel 32-Bit microcontrollers with advertised 66-Mhz or 80-Mhz clocks refers to the internal instruction execution rate not I/O speed. I'll take a look at Microchip and Atmel micro offerings and maybe email the manufacturer to find out what maximum frequency their GPIO lines can reach.

By the way, how "buggy" is WinAVR? Have you had good experiences with it?

dknovick

Actually, it's probably the external clock. PICs run at 1/4 the external clock (at least the 8bit microcontrollers). However, depending on how often you want your 30.5ns pulse, you could set up a hardware timer (compare or PWM), which might get you your pulse.

WinAVR: I can't speak for any 32 bit compilers, but with my limited experience, I had no trouble with WinAVR. We had a robotics project at work, and one of the coders hates windows. So he used the cross compiler under linux. Aside from a few #define statements, his code, and one generated from an expensive compiler where compatible.

-Dave