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Serial comms between two microcontrollers - not working!

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Why not use max232 to your uC (for testing only) you have it already, it's tolerance to voltage variation is greater than the micro, you might be missing some voltage level which is confusing the receiver, there's no problem in code because you can connect to your pc.
 
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penoy_balut said:
Why not use max232 to your uC (for testing only) you have it already, it's tolerance to voltage variation is greater than the micro, you might be missing some voltage level which is confusing the receiver, there's no problem in code because you can connect to your pc.


Hi, thanks,

But the chip only understands RS232 Voltage levels as input which is +/- 10V
uC is TTL level +/-5V. Or it understands TTL input voltage and outputs RS232 voltage levels.

Neither works.

How would I connect it? Thanks.
 
Its working! God be thanked.

Thanks to all for your help.I think it is to do with me specifying my charecters to be transmitted in binary ie. 0001001B instead of 9 in decimal or hex. Though I dont know why would make a difference as I am essentially doing the same thing. However when I changed the way I described the data I wanted to transmit, it worked.

Oh well.

Thanks again for all the help. Much appreciate it. :)
 
AceOfHearts said:
Its working! God be thanked.

Thanks to all for your help.I think it is to do with me specifying my charecters to be transmitted in binary ie. 0001001B instead of 9 in decimal or hex. Though I dont know why would make a difference as I am essentially doing the same thing. However when I changed the way I described the data I wanted to transmit, it worked.

Oh well.

Thanks again for all the help. Much appreciate it. :)

Wow that is pretty wierd. Sounds like a assembler or compiler bug, what programming SW are you using? Can you look at a hex listing of the output code to see what the difference is between the two cases? Eight bit being set?

Lefty
 
there is this document about UART provided by atmel.. i owe it a lot in serial programming it is simple and straight fwd...

**broken link removed**
 
Leftyretro said:
Wow that is pretty wierd. Sounds like a assembler or compiler bug, what programming SW are you using? Can you look at a hex listing of the output code to see what the difference is between the two cases? Eight bit being set?

Lefty

Hi, thanks.

Ok I will give that a go when I find some time and get back to you.
 
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