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fdosa

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Reply with quote  #1 

Hello! Everyone! I have some problems in my project.

Here is my issue, it appears that all the communication lines for the PIC16F913 reside on the same set of pins, this is convenient in that I don't have to sacrifice GPIO pins just to do comms, however the problem I'm having now is if I'm using the SPI on the chip, how can I send information to the RS232?


The reason this issue came up, is that I just bought a CAN bus chip that communicates over SPI, and I would really like to see the data on RS232, so I can see messages. (I really don't know much about CAN yet, so who knows if this even makes sense yet).

Here are the options I see, and maybe someone else has better ideas that I'm just simply missing.

Somehow setup a time scheme that will switch between SPI and RS232 every time I get data, -- This doesn't seem hard and should work, but supposing I don't want to miss a message, what if a message is written while I'm writing to RS232, is it possible I'll miss it?

2.. I can always use SPI, but then build my own comm bus over 8 of the GPIO lines, to another PIC16F913 using only the GPIO lines and then since the RS232 lines are free on the second PIC I can simply read the data and spit it out.

-- This one is doable but now we're wasting 2 chips, AND all the GPIO lines,

There has to be a better way. Or is there?

Any help is greatly appreciated.

I would like to also clarify, obviously one solution is using a completely different chip (which may in fact be what I end up doing, if I can get the 18F programmed), however, I'm interested in worst case scenario, in which I am limited in resources and only have some 913's, is the way described above the only way to do it with this chip, or is there a better way?

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ampman

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Reply with quote  #2 
I understand your question, but never used PIC processors myself. Have used Arduino though, in fact one with a built in screen called the Microview (about £30) which could potentially show messages on the built in display, and the SPI pins are still free on that.

What's your project doing? Are the messages going in real time via RS232 to a computer program that's displaying them?
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