RS232 at 57600 bps via joystick port

By RvS

Rookie (24)

RvS의 아바타

12-05-2020, 21:24

The last months I have been trying to get a stable serial connection between a FT232 module and my MSX (NMS8245).
I believe it is working now. It is still a very basic driver: just sending and receiving bytes at 57600 bps. Pin1 is RX (input) and pin6 is TX (output).
The code is avialable here: link
It should work on a 'normal' MSX with a 3.58 MHz Z80.
The key trick was fast polling for the start bit followed by a strict 62 cycles loop to read all data bits.
The Z80+M1 table from Grauw was extremely useful here!
The next step in this mini-project is creating file I/O routines.

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By kaizen4871

Supporter (5)

kaizen4871의 아바타

12-05-2020, 23:00

awesome! thanks a lot. looking forward to hear about the mini project.