clivemist:
Hi dc42.I am getting similar issues as this with a 328p-au..
I've tried alsorts but am a bit stuck:http://arduino.cc/forum/index.php/topic,129740.0.html
Any ideas?
Thanks in advance.
Looking at your post #7 in that thread, you are setting the baud rate to 300 on the mcu but then you have to set the PC to 2400 to communicate with it. So the UART in the mcu is running 8x faster than it should be. This isn't a problem with the CLKSEL fuse bit, that would cause the mcu to run 8x slower instead.
Are you sure that you have F_CPU set correctly in the boards.txt file you are using? Do you also find that delay and delayMicroseconds calls also execute 8x faster than they should?