Ok so, here is my ps2 to x68k keyboard converter. I've quickly designed it while studying the MFP inside the IO board. Unlike the known one, it use an atmega32 from atmel, but with a bits of modifications, it should work with any kind of avr that support uart and external interrupts. (I've also test it with an atmega644p).
I provide it with full source code, nicely commented for those who are interested, and ready to be build with avr-gcc and avr-libc under linux (I don't really know what tools is available under windows for avr development, I've heard about a "winavr"...)Source code here
Sorry, I don't provide a PCB yet, I would like to do some reworking on it first (using a smaller mcu, adding keyboard leds handling and key repeat/delay time, mouse, ...)
Oh also, here is a note about the keyboard port : I don't know why, but all the mini din7 keyboard pinouts informations I have found on japanese sites are all wrong ! The "Remote Signal" and "Ground" are inverted.
Here is the correct one : (Traced myself from the IO board. View is from front of the x68000, the female connector)
Signal description :
- KBD_TX : Connected to MFP usart transmitter. Used by host to send command to keyboard (leds on/off, key repeat/delay, keyboard/mouse turn, ...)
- KBD_RX : Connected to MFP usart receiver. Used by the keyboard to send its keystroke to host.
- KBD_READY : Connected to MFP signal #RR, this is just an information signal asserted when MFP usart receiver is full. (like too much data from keyboard)
- KBD_MS_DATA : Mouse Data from keyboard. Connected to SCC channel B, shared with the mouse connector. (Yes, it seems some keyboard can attach a mouse. Seems configured as 4800bps,8N1. must study more
- KBD_RS : Remote Signal (must study
-+5Vsb : +5v stand by from psu. Keyboard seems to be always powered (some kind of remote wake up ?)
-Gnd : Ground.
That's all ! Have fun !