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robdobsn / BusRaider

Play vintage computer games on real hardware, single-step debug Z80 programs and test new hardware with the BusRaider for RC2014. https://robdobson.com/2018/08/trs80-galaxy-invasion-on-rc2014/ and https://robdobson.com/2019/06/what-can-you-do-with-a-busraider-part1/
https://robdobson.com
MIT License
20 stars 3 forks source link

Fix port 2 txPin #4

Closed Simulators closed 4 years ago

Simulators commented 4 years ago

There is a bug in the ESP32 code which prevents keyboard input or Telnet input from reaching the backplane serial line when 6850 emulation is turned off, for example when using a real SIO/2 UART board. The Machine Interface serial port 2 is using pin 25 (ESP32_IO25) as the txPin to the backplane, but the board has ESP32_IO27 connected to that line, on both PCB 2.01 and 2.2.

ESP32_IO27 is wired to pin 3 on the expansion connector, and a workaround can be demonstrated by removing the relevant jumper from the serial select bank, and then jumpering the "Z80" pin on the serial select bank to pin 3 on the expansion connector (which is a bit fiddly because the Pi is in the way). ESP32_IO27 is not used anywhere else on the schematic.

Fixed and tested in this commit, and it now works fine with the 6850 emulation turned off, including USB keyboard input and the Telnet interface. Tested on PCB v2.01, and checked the schematic for PCB v2.2 and found the same problem. Older PCB versions not checked.

robdobsn commented 4 years ago

Thanks Andrew for fixing this, the code change has been incorporated now.