different Project using rs-232 and PWM carrier sg, possible?

[cagacug]

Hi to Everyone,

I am trying to build a little different project which uses soft rs-232 and 20kHz signal as a carrier for rs-232.

I did this with a hardware version, I mean I add the output of rs-232 pin with 20kHz signal which I produce with an oscillator, and it is working. But in order to free some space and components I want to this with software.

In other words, I want to define rs-232 and pwm, when the soft tries to transmit rs-232 data, it will actually enable the pwm output with 20kHz. But how can I define that the tx pin will actually enable the pwm output? OR can I change the internal rs-232 function to do this? Rx pin will work as it is. Any ideas?

Thanks,

[Mark]

You will have to bit bang the data out or use a hardware solution that "ANDs" the pwm and rs232 signals together.

[cagacug]

Thanks for the reply.

Can you explain or give example of "bit bang" ing?

[Mark]

Set pin high
wait
set pin low
wait
and so on


This means that you must manually create the waveform by toggling a pin!