That's really strange. I cannot see what could generate 7.5MHz on the processor's TX pin. The processor could not generate a signal at that frequency. Sorry if this is a dumb comment, but are you 100% sure you are counting/identifying the IC3 pins correctly??
On Wed, Nov 22, 2017 at 4:36 PM, Dave Lear <de.ne5dl@...> wrote:
Hi Hans
I have the opposite of the requirements. That is:- 25mV on pins 4/10. 5V peak to peak square wave at 7.5mHz on pins 5/11. This is labeled? "TX" on the circuit daigram. 13V power supply This is with the LCD unplugged.
