Re: [Amforth-devel] Atmega8 uart issues.

[Erich W. <ew....@on...>]

Hello,
and "welcome" :-)

Matt Eastburn wrote:

> I have just set up a basic project to see if I can get something out  
> of the serial port.
> 
> At this stage can't get it to do anything on the serial port.

This could unfortunately be any number of things ... so 
without more details (exact controller, crystal or internal 
oscillator, at what speed ...) this is hard to "debug".

My suggestions:

1. go to very low speeds on the serial port, maybe 1200 
baud, just to see, if bits go across the line. Use an LED 
with a resistor as a "probe". Just to make sure there are 
pulses on the cable connections.

2. I had similar problems with an atmega32. They were fixed 
by using a "baud rate crystal" (11.0592 MHz) and better fuse 
settings (I had to dig deep in the datasheet: hfuse=0x89, 
lfuse=0xee). This setting now works reliably with 115200 baud.

3. To make things a little more "obscure", the programmer I 
used initially, did not release the /Reset line properly. So 
unplugging the damn thing made much of a difference :-)


Good luck!
Erich


Good luck!