Logic Analyzer

It seems to work. Now I only have to make the rest of the code live with it in peace. That doesn't work 100% right now. The LED driver interrupt gets upset sometimes. The entry points of the pin-change ISR are marked with double-pulses, sampling the data is marked by single pulses. Spikes 2-9: sampling the data byte, spike 1: start bit, spike 10: stop bit, spike 11: hmmmm ?!?

Just testing the analyzer a bit. Unconnected probes pick up noise quite a lot.

I ordered it yesterday morning and got it tonight ;-)

settings: 9600,8,N,1 de.wikipedia.org/wiki/RS-232 "start bit - 01000110 - stop bit" (LSB first!) equals 0x62 The purple-ish markings don't quite fit time-wise. I've put cursors at the byte boundaries.

Remember: always, no ALWAYS add some means of getting signals out.

Remember: always, no ALWAYS add some means of getting signals out.

By accident I stumbled across my 'system-ticker' interrupt today. As it happens it conveniently ticks at 1MHz! One tick of timer0 is one microsecond. Microsecond timing is exactly what is needed for receiving serial data. The sampling interrupt (TIM0_COMPA_vect) is now invoked at the right time by setting OCR0A = TCNT0 + FULL_BIT_DELAY.

By accident I stumbled across my 'system-ticker' interrupt today. As it happens it conveniently ticks at 1MHz! One tick of timer0 is one microsecond. Microsecond timing is exactly what is needed for receiving serial data. The sampling interrupt (TIM0_COMPA_vect) is now invoked at the right time by setting OCR0A = TCNT0 + FULL_BIT_DELAY.