AVR Assembler: Debugging IR Remote Control Transmitter

Johannes F. wrote:

I connected a red LED to the output which produced the result

A flashing LED is way too little to debug a serial interface. You should connect a oscilloscope instead. Because with that you can determine the real pulse times and check it against the mentioned https://www.mikrocontroller.net/articles/IRMP_-_english#NEC_+_extended_NEC and find out the factor your timing is wrong.

When its "fairly ecacxt" the factor 8 you shuld check the correct setting of the clkdiv8 fuse in your AVR.

Lothar M. wrote:

You should connect a oscilloscope instead.

Yes, that's true of course, but unfortunately I don't have a DSO at the moment.

Lothar M. wrote:

When its "fairly ecacxt" the factor 8 you shuld check the correct setting of the clkdiv8 fuse in your AVR.

I already checked that; it's not programmed (i.e. value 1). I used the UART successfully with the same hardware directly before I flashed the current program, so the clock frequency has to be correct.

(Wilhelm M. - are you watching?)

Well now how about that?:

1

 ldi   temp0, 1<<WGM12  ; CTC mode

2

 xout  TCCR1A, temp0

WGM12 resides in TCCR1B.

S. L. wrote:

WGM12 resides in TCCR1B.

Oh yes, that was a mistake – thank you!

I corrected that and, in addition, another error (forgot to clear the COM0A0 bit of TCCR0A in the ir_carrierOff macro, which caused the LED not to be switched off at the end of every other transmission).

Now, it works perfectly.

Again, S. L., thanks for your help!

Have a nice evening, – Johannes