big-banged serial port decoder
Posted: Fri Nov 03, 2023 1:40 am
Hi,
I'm working on a new driver, where the firmware outputs early diagnostic codes via CPU driven beeps, and also a software driven (bit-banged) serial port. I am wondering if there exists a driver to decode this in software. It's just a GPIO pin toggled by the CPU with busy loops for timing, so it's not just a simple capture of a holding register. Conceptually it might be similar to a 1 bit DAC audio output, with a decoding routing reading the samples and detecting the start bit, data bits, stop bits, etc.
Cheers, and thanks for MAME, the C++ tutorial system
I'm working on a new driver, where the firmware outputs early diagnostic codes via CPU driven beeps, and also a software driven (bit-banged) serial port. I am wondering if there exists a driver to decode this in software. It's just a GPIO pin toggled by the CPU with busy loops for timing, so it's not just a simple capture of a holding register. Conceptually it might be similar to a 1 bit DAC audio output, with a decoding routing reading the samples and detecting the start bit, data bits, stop bits, etc.
Cheers, and thanks for MAME, the C++ tutorial system