>> Having a peek at the keyboard scanning code in VICE, it seems that an >> opportunity may have been missed. This missed opportunity was the >> ability to isolate joystick activity from a keyboard scan. >> Once the job of sending the column signals was taken over by the 6529 >> from the data buss, writing data with bits 1 and 2 set (EG $ff, or $06) >> to the TED keyboard latch would ensure that the joysticks could not >> interfere with the keyboard scan. > > Yeah, I've been wondering about that too. I can see no reason why the > joysticks had to be left active there either. > >> By adding 2 bytes, simply changing it to: >> >> STA $FD30 ;Write to 6529 - Column >> LDA #FF ;disable joystick probe >> STA $FF08 ;Write trigger to latch TED keyboard input >> LDA $FF08 ;Read latch (Row) >> RTS ;Return >> >> The Joysticks could be left turned off for the duration. > > Yes. That's how it should have ended up IMHO. > That's precisely what I did in Diag264: lda #$fd ; check shift lock sta keyport_6529 lda #$ff ; stop joytest interfering with kb sta TED_Latch lda TED_Latch I had the requirement to have loopback dongles simultaneously on the KB & joystick ports so I needed to do this to prevent conflicts; and it works perfectly well. Rob Message was sent through the cbm-hackers mailing listReceived on 2013-09-09 10:01:12
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