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89 lines
2.5 KiB
89 lines
2.5 KiB
;
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;==================================================================================================
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; NABU HARDWARE DRIVER
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;==================================================================================================
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;
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; NABU INTERRUPT ENABLE PORT AND STATUS PORTS ARE MANAGED BY THE
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; PSG IO PORTS.
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;
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; NABU CONTROL PORT - INTERRUPT ENABLE (OUTPUT) - PSG PORT A
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;
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; D7 - HCCA Receive
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; D6 - HCCA Send
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; D5 - Keyboard
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; D4 - Video Frame Sync
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; D3 - Option Card 0 (J9)
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; D2 - Option Card 1 (J10)
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; D1 - Option Card 2 (J11)
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; DO - Option Card 3 (J12)
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;
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; THE CONTROL PORT IS WRITE ONLY AND THE BITS NEED TO BE MANAGED IN
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; MULTIPLE DRIVERS. BELOW, WE ALLOCATE NBAU_CTLVAL AS A SHADOW
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; REGISTER FOR THE CONTROL PORT. IT IS INITIALIZED TO ZERO HERE
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; (ALL INTS DISABLED). THE INDIVIDUAL BITS ARE SET AS APPROPIATE IN
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; THE DRIVERS THAT WANT THE INTERRUPTS ENABLED (NABUKB, TMS).
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;
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; NABU STATUS PORT - STATUS BYTE (INPUT) - PSG PORT B
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;
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; D7 - N.C.
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; D6 - Overrun Error (HCCA UART)
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; D5 - Framing Error (HCCA UART)
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; D4 - Printer Busy
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; D3 - A2 Priority
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; D2 - A1 Priority
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; D1 - AO Priority
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; DO - Interrupt Request
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;
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; PORTS TO MANAGE PSG
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;
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NABU_BASE .EQU $40 ; BASE PORT FOR NABU PSG
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NABU_RSEL .EQU NABU_BASE + 1 ; SELECT PSG REGISTER
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NABU_RDAT .EQU NABU_BASE + 0 ; WRITE TO SELECTED REGISTER
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NABU_RIN .EQU NABU_BASE + 0 ; READ FROM SELECTED REGISTER
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;
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DEVECHO "NABU: IO="
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DEVECHO NABU_BASE
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DEVECHO "\n"
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;
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; HARDWARE RESET PRIOR TO ROMWBW CONSOLE INITIALIZATION
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;
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NABU_PREINIT:
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;
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; RESET SHADOW REGISTER IN CASE WE ARE DOING AN HBIOS
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; RESTART IN PLACE
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XOR A ; ALL INTERRUPTS DISABLED
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LD (NABU_CTLVAL),A ; SAVE IT
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;
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; INITIALIZE THE NABU PSG I/O PORTS
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; PORT A (CONTROL PORT) IN WRITE MODE
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; PORT B (STATUS PORT) IN READ MODE
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; INITIALIZE THE CONTROL REGISTER
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;
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; SET I/O PORT MODES
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LD A,7 ; PSG R7 (ENABLE REG)
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OUT (NABU_RSEL),A ; SELECT IT
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LD A,%01111111 ; PORT B INPUT, PORT A OUPUT, AUDIO CHANNELS DISABLED
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OUT (NABU_RDAT),A ; SET IT
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;
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; INITIALIZE PORT A VALUE
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LD A,14 ; PSG R14 (PORT A DATA)
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OUT (NABU_RSEL),A ; SELECT IT
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LD A,(NABU_CTLVAL) ; GET CTL VALUE SHADOW REG
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OUT (NABU_RDAT),A ; WRITE TO HARDWARE
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;
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XOR A ; SIGNAL SUCCESS
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RET ; DONE
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;
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; POST CONSOLE INITIALIZATION
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;
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NABU_INIT:
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CALL NEWLINE ; FORMATTING
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PRTS("NABU: IO=$")
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LD A,NABU_BASE
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CALL PRTHEXBYTE
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XOR A ; SIGNAL SUCCESS
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RET ; DONE
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;
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; DATA STORAGE
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;
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NABU_CTLVAL .DB 0 ; SHADOW VAL FOR NABU CONTROL REGISTER
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