Choosing a PIC for my project...

[Beef41]

Sorry to burst onto the scene and ask for a favor from you good folks, but I am overwhelmed with information on PICs. That and I have trouble choosing what type of jelly to put with my peanutbutter, much less something hard like this... {grin}

So I was looking at all the PICs that Microchip has to offer, and I'm lost. I have programmed the MC68HC11, but I've never worked with a PIC before. I've heard that all newbies should start with the 16F84A, but I don't know if that will work for my project.

I am building a voice controlled wheelchair for quadrapalegics. The voice recognition chip has 9 output pins. I will be only using 5 of those pins... for the time being, anway. That will be the input side of the PIC. The PIC will control the left and right side motors, through some control circuitry. The control circuit needs one PWM {Pulse Width Modulation} line and one control line per motor. The code for the PIC should be rather simple. I hope it will be, anyway.

So totalling that all up I have:
5-9 inputs
2 PWM outputs
2 control line outputs
? unknown inputs/outputs*
Simple code

*The unknowns are probably nothing, but as with any project, there is always something that you've missed on the first glance... and I tend to miss a lot.

I looked at the data sheet for the PIC16F84A from Microchip, but I don't think it supports PWM. So, any suggestions what I should use for this project?

So the 64k dollar questions are.... Will the 16F84A work for this? Is there a better solution for a newbie to use? Should I just use a 68HC11 instead? Any advice on this project that you would like to share with me? What is the meaning of life? Have I asked enough questions yet?

Beef 41

P.S. If you need more information on this project to give me a meaningful answer, please ask. I'll be back every day or so to fill in the details.

 

[Nigel Goodwin]

I looked at the data sheet for the PIC16F84A from Microchip, but I don't think it supports PWM. So, any suggestions what I should use for this project?

The 16F84 series is pretty well obselete, it's been replaced by the 16F628, which is cheaper, has more facilities, and is pin compatible - I would recommend the 628 for a beginner. My PIC tutorials use the 628 for this very reason.

One of the extra facilities is a single PWM channel, and it also has an internal 4MHz oscillator - it should be perfect for your project.

 

[kentken]

The 16F87x series has a lot of options built in, I don't like to use any less then this series. One thing that come in handy is the ISP, and the ease of programing.

Kent

 

[Beef41]

The 16F84 series is pretty well obselete, it's been replaced by the 16F628, which is cheaper, has more facilities, and is pin compatible - I would recommend the 628 for a beginner. My PIC tutorials use the 628 for this very reason.

One of the extra facilities is a single PWM channel, and it also has an internal 4MHz oscillator - it should be perfect for your project.

Wow. Ok, that's some really good advice, an internal oscillator would be really helpful. I checked out your tutorial as well, and I'll be using a lot of that information.

However, I'll be needing two PWM channels, so I don't think that the 16F628 will be quite good enough...unless I've overlooked something. Is there a similar chip with two PWM channels on it?

BEEF 41

 

[Nigel Goodwin]

However, I'll be needing two PWM channels, so I don't think that the 16F628 will be quite good enough...unless I've overlooked something. Is there a similar chip with two PWM channels on it?

You only asked for one before!, which was why I suggested the 628. I don't know of a similar chip with two PWM's - although there have been a lot of new FLASH chips appearing lately. For two PWM channels I would use the 16F876, it's a 28 pin 'skinny DIP' chip, but requires an external oscillator. It's simply a smaller version of the 16F877, which is a huge 40 pin chip. One of my tutorials deals with using the two PWM channels to control two motors for a simple robot or remote control vehicle.

 

[e]

I like the 18F1320, 8MHz internal osc. 1,2, or 4 PWM all in a small 18 pin chip

 

[Zac S]

Sample 18F code

Anyone know any sites that have some sample code and programs for the 18F series. I want to try to use those instead but its always nice to see a program to learn the caveots of the chip.