Hi I am solving simple problem.
I need control GSM module with HW UART
but I need also debug output channel.
I dont wish use SW_UART like bit-bang with pin becouse all pins are used
but I have one LED/pin available where can be tempovery relay during development phase
I am asking gurus if is possible
attach on single TX wire
PC terminal and SMS module
and with LED pin control relay during debugging
relay will cut-off sms module.
when my debug_printf() will send debug message to PC. after printing debug info will relay again wire SMS module.
Exist any other "clever" solution howto do that If I need SW multiplexing on single HW UART device?