Some background: I'm updating my C64 Burstloader routine. > C128 sends a fast byte, toggling the SRQ line eight times, with the > ATN line low. This I knew, or at least guessed. The loader sends a byte to flag to the drive that we can indeed synchronous serial. But, I'm sending it before anything else is done, no device is accessed, and it doesn't seem to matter. > and respond with a fast acknowledge. I found the relevant part of the C128 ROM code. The detection is in SECOND (executed as part of CHKOUT): .$e3b6 pha ; [ $48 ] .$e3b7 lda $dc0d ; [ $ad $0d $dc ] .$e3ba and #$08 ; [ $29 $08 ] .$e3bc beq $e3c3 ; [ $f0 $05 ] .$e3be lda #$c0 ; [ $a9 $c0 ] .$e3c0 sta $0a1c ; [ $8d $1c $0a ] .$e3c3 pla ; [ $68 ] The problem now is: the C64 ROM clears $DC0D status in SECOND.. I would need to duplicate huge amounts of code just for fast serial capability detection. Well, actually, there is a way to get over this: I can use the other CIA i.e. the other synchronous serial port.. Thanks anyway for the info, although it didn't help much. -Pasi -- "The third principle of sentient life is it's capacity for self-sacrifice. For a cause, a loved one, for a friend." -- Delenn to Draal in Babylon 5:"A Voice in the Wilderness #2" - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
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