I have just switched from powering my micro with 3.3v to 1.8v and now the micro and i think usart does not work. I cannot test the output of the usart because the ttl level is below 3v.
I am running 4MHz and 9600 baud. Is this to much for a 1.8v supply. Should I drop down to 1MHz.
Other than swapping from 3.3v to 1.8v I have changed nothing else. Do I need to changed anything else when dropping the supply voltage?