cheap PIC w/ CAN?

jma_1 · Joined: 08 Feb 2005 Posts: 147 Location: Wisconsin

Greetings,

I'm looking for suggestions on an inexpensive 8 bit processor with CAN. The PIC 18F2480 looks like the least inexpensive offered by Microchip. The part is ~ $5 - 6 with extended temperature range and quantity. However, I do not need all the 25 I/O pins (overkill). I'm looking for ~ 10 I/O with CAN (but cheaper < $5).

Any suggestions? How about Atmel, Siemens, TI, Holtek, Renesas, Freescale or ? How about using an FPGA w/ a soft-core CAN module?

Thanks for your time,

JMA

jecottrell · Joined: 16 Jan 2005 Posts: 559 Location: Tucson, AZ

PIC (get it?) your MCU and then add a CAN transceiver (MCP2551 $1.45 ea. @ Digikey).

Quick, simple, and easy.... No?

Good luck,

John

kender · Joined: 09 Aug 2004 Posts: 768 Location: Silicon Valley

jecottrell · Joined: 16 Jan 2005 Posts: 559 Location: Tucson, AZ

Nick,

I just looked at an app note AN212 and it uses a MCP2510 then a MCP2551. So apparently more hardware is involved, i.e. a CAN controller then a CAN driver. I'm learning as I go.......

So, to use a smaller PIC would require two extra peripheral devices with their added cost, complexity, and supporting components.

I would go with the PIC with on board CAN and leave the unused IO alone....

John

Storic · Joined: 03 Dec 2005 Posts: 182 Location: Australia SA

Yep,
I went through a similar exercise where I wanted to use a small 24F micro, it looks like I will be using the 100 Pin version for the peripherals instead of adding the extra's. As for the spare pins, I layed the board out so I could access them easily so if I was looking at changes, extentions or even a new design I counld use this board.

Andrew
_________________
What has been learnt if you make the same mistake? Wink

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

Some info on several of all possible manufacturers:
- Microchip, many choices. PIC18F2480 starts from $4.30
- Atmel has only few CAN processors. AT90CAN128 too expensive, cheaper AT90CAN32 starts sampling 06Q3
- Philips, several ARM based processors: LPC2119 from $7.60
- Renesas has several processors with CAN, and many under development. H8 based HD64F36054 from $8.60

For processors from other manufacturers you'll have to do your own investigations.

jma_1 · Joined: 08 Feb 2005 Posts: 147 Location: Wisconsin

Thanks ckielstra,

I found the same processors you listed. If I find anything less expensive I'll post a link to it.

Cheers,
JMA

iso · Guest

jecottrell, the 2551 is just a transceiver. You must mean a stand-alone can 2515 right ?

Don't worry about 'wasting' io pins as long as you have the room for the package it doesn't matter. I've found I will always end up needing at least 2-5 more io pins then I originally figure when doing a new project.

The 28pin QFN pics are the smallest processors with CAN anywhere out there I beleive.

I've dealt with microchip can a lot and I recommend it. Not overly complicated and I have yet to find any glaring design flaws. I have no reservations about using microchip CAN in any of my projects.

Try pic with internal can + transceiver (2551 is decient and cheap) or you have the small cheap pic + 2515 + 2551. The only requirement you have with the 2515 option is your pic should really have hardware spi... but you could do it in software.