[recommend]18f MCU

biomed12 · Joined: 05 Feb 2016 Posts: 33

Hello Dear Forum CCS family,

A few months later, i will start using again PICs and CCS language for a part of my graduate project. I need your unique experiments with PIC.

The part is related to connect a PIC to internet and also i want to run it at a high freq. more than 20 MHZ (at least). Also its other task is about running a signal processing algorithm. (Maybe i can use another pic for that, i haven't decided yet). The last thing, i want much memory like 96K. I want to do a complicated project and i will use its pins as i can and i will try to run a lot of peripheral module to make my work perfect as it would be possible.

Briefly, do you know for me a perfect PIC, I don't mind about its prices.

(I am not rich, just PICs are very cheap:)

Thanks...

temtronic · Posted: Thu Aug 11, 2016 8:51 am

What's your education( hands on experience) related to PICs ? Which PICs have you used in real hardware applications ? Have you done any CCS C programs ? Looked at their examples( 100s of them !)

Connecting a PIC to the Internet is not specific as it can be done using hardwire or wireless, say though a router or server. HUGE difference in the approach and what you need. Something like an esp2866(?) may 'link' a PIC to the Net for a few bucks....

Speed >20MHz, not a problem, any of the PICs with PLL can do that. Though speed is NOT the main criteria for a 'good' system.

96K of memory ? Unless you're a really sloppy programmer, 32 or 64K should be lots. Heck my remote energy control system with 512 remotes
only needs 8KB of space and it has LOTS of 'features'.

The major problem that you have is TIME ! a 'few' months is NOT enough unless you start today, plan your project and get coding ! There is a 'learning curve' to every PIC and compiler. That alone could take months just to get reasonably good. You need to break down your project into small 'sub programs', get each one working, then move on. It's the 'details' that will slow you down to a crawl.

My choice(as others know) is the PIC18F46K22. Fast,lots of I/O, lots of memory, a 'solid' stable product.One of many that can run at either 5v or 3v at full speed, critical when interfacing to peripherals, like the 'internet interface device'. While you can make your own PCB or use a 'breadboard' consider buying a 'protoboard WITH 46K22' already mounted. It WILL work 'out of the box' and save you hours or days trying to figure out why your homemade perfboard doesn't run. Be sure to get the 1Hz LED and the 'Hello PC' programs running BEFORE even thinking of cutting code for your 'project'.

Jay

ckielstra · Joined: 18 Mar 2004 Posts: 3680 Location: The Netherlands

For a good advice we need a lot more details about your project, like:
- What is your project about?
- What processor types do you have experience with?
- Why do you want to use a PIC processor?
- You mention 96k memory. Why this amount? Is this RAM or ROM memory?
- How many units are you going to build?
- How important is price? (spending a little bit more can sometimes save a lot of time)
- Is tiny size important?
- etc.

Using a PIC for an internet connected device is possible but wouldn't be my first processor of choice. The PIC16 and PIC18 processors have little RAM which complicates ethernet communication. It is possible, but without more details about your project we don't know which corners can be cut.
PIC24 are newer chips with more capabilities.

Don't fixate on the cost of the processor. The suggested PIC18F46K22 costs around $3. You need a PCB, connectors and some other parts and before you know it the whole unit costs $25 to $75. For these prices you might as well consider a much more powerful Raspberry Pi board for around $45, or another ethernet enabled board from this selection. Those boards use an ARM processor with loads of RAM, ROM and processing power, prices starting at about $20. This saves you a lot of time to get your project going.

biomed12 · Joined: 05 Feb 2016 Posts: 33

biomed12 · Joined: 05 Feb 2016 Posts: 33

guy · Joined: 21 Oct 2005 Posts: 297

Implementing a DSP filter depends on the processing speed that you need: If you have want to measure heartbeats for example, it doesn't require fast processing and a PIC can easily handle it. If you need to analyze 3-axis accelerometer signals to keep a toy helicopter (or a real helicopter) hovering, there is much more processing and much higher rates required.