Re: What bus should I use? I2C, SPI or something else?


I've not heard of CAN. I was mainly looking at I2C as it seemed the
most sensible, I hadn't read too much on SPI.. I didn't realise it
didn't support addressing, which rules it out.

One of the reasons I2C and SPI came it mind is they are natively
supported by the PIC processors I'm intending to use. Obviously using
RS485 would be quite possible, but it requires driver chip on each
module. Having said that I'm guessing I'd need some protection on the
PIC pins incase of shorts etc?

Something I forgot to mention. I'm intending on running this from a
lithium ion battery, so I'd get about 3.7volts to power the components.
Can RS485 be driven from that?

While I know RS485 is designed for stability, could I2C be stable in
that environment running at 400Khz? Or would I have to drop it to
100Khz, in whichcase I guess async serial over RS485 would be faster at
115.2Kbit. I guess it comes down to will it work, and would the
component count/cost of RS485 be much higher?

Michael

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