http://bitchin100.com/wiki/index.php?title=BCR_TTL_SERIAL_HACK
this hack works well with 8085, based on SOD, I am working on an NSC800 version, so that "Z80" modified M100s can also transmit video data out the BCR port. Background: SOD pin, normally used to drive the cassette port, can be used as a bit banger Tx output. Wiring it directly to the BCR port makes a bi-directional TTL serial port. NSC800 does not have a CPU bit-banger port like SOD pin. So something else is needed. Turns out there is an unused I/O port, /Y1, on M100. That can also be used to generate bit-banged serial data. So, I am working on a version that uses the /Y1 port. code is slightly different, ..Steve
