mirror of
https://github.com/erangell/A2NoSlotMIDI.git
synced 2024-10-31 19:05:12 +00:00
385 lines
14 KiB
ArmAsm
385 lines
14 KiB
ArmAsm
;-------------------------------------------------------------------------
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; APPLE ][ SERIES ANNUNCIATOR MIDI DRIVER
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; Copyright © 1998-2018 Eric Rangell. MIT License.
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;-------------------------------------------------------------------------;
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; main.s
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; A2NoSlotMidi
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; Created by Eric Rangell on 17 JULY 2018.
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; VERSION 1.0.1 released 26 JULY 2018
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; VERSION 1.0.2 released 29 JULY 2018
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;-------------------------------------------------------------------------
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; THIS DRIVER IMPLEMENTS ASYNCHRONOUS SERIAL DATA TRANSMISSION
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; THROUGH AN APPLE ][ ANNUNCIATOR OUTPUT PORT OF THE GAME CONNECTOR
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; USING 32 CYCLES PER BIT TO ACHIEVE A 31.25K MIDI BAUD RATE.
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;
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; APPLE //GS USERS NEED TO RUN THIS PROGRAM IN NORMAL SPEED MODE (1MHZ)
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;
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; THE OUTPUT IS INITIALIZED TO A HIGH LOGIC VOLTAGE. WHEN IT GOES
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; LOW FOR 32 MICROSECONDS, THAT INDICATES THE START BIT OF A MIDI BYTE.
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; THEN 8 BYTES OF DATA ARE TRANSMITTED, FOLLOWED BY A HIGH STOP BIT.
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; THE DATA BYTES REPRESENT MIDI MESSAGES WHICH CAN BE INTERPRETED BY
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; ANY MUSICAL INSTRUMENT THAT IMPLEMENTS MIDI.
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;
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; ENTRY POINTS: (Note: Origin must be set in Makefile)
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;
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; $9000 = INITIALIZE - TURNS ON ANNUNCIATOR 0 - MUST BE CALLED ONCE
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; $9003 = APPLESOFT CALL TO SEND ONE MIDI BYTE. POKE THE BYTE IN $9004.
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; $9005 = ASSEMBLY CALL TO SEND ONE MIDI BYTE FROM ACCUMULATOR
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; $9008 = APPLESOFT OR ASSEMBLY CALL TO SEND SEVERAL BYTES AT ONCE:
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; THE CALLER POPULATES LOCATION $D7 WITH THE NUMBER OF BYTES TO BE
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; TRANSMITTED, AND A POINTER IN $CE,CF (LO,HI) WITH THE ADDRESS OF
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; THE DATA BYTES, THEN CALLS THE ENTRY POINT "SENDMSG" TO TRANSMIT
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; THE MESSAGE.
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; $900B = TURN ALL NOTES OFF
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; $900E = SEND A TEST MESSAGE - C MAJOR CHORD NOTE ONS
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; $9011 = SEND A TEST MESSAGE - C MAJOR CHORD NOTE OFFS
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;
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; IF THE FOLLOWING ROUTINE IS USED, IT SHOULD BE CALLED IMMEDIATELY AFTER BLOADING
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; THE BINARY. AT THE END, IT WILL CALL THE INIT ROUTINE FOR THE SELECTED ANNUNCIATOR.
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;
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; $9014 = CHANGE ANNUNCIATOR - MODIFIES CODE TO USE DIFFERENT ANNUNCIATOR
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; $9017 = ANNUNCIATOR TO USE: 0-3 - only looks at least significant 2 bits
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;
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; $9018 = SET TO 1 TO USE NEGATIVE LOGIC (ONLY ONE INVERTER IN THE MIDI CIRCUIT)
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;-------------------------------------------------------------------------
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; Enhancements for 2018:
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; 1. Disable interrupts during critical timing sections, preserve interrupt status
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; 2. Entry point to reconfigure program to use a different annunciator pair
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; 3. Entry point to reconfigure program for hardware interface using inverters only (not buffers)
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;-------------------------------------------------------------------------
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; CALLER MUST POPULATE THE FOLLOWING TWO ZERO PAGE LOCATIONS FOR SENDMSG:
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NUMBYTES = $D7 ;NUMBER OF BYTES TO BE TRANSMITTED NOW (1-256)
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; ;THE VALUE 0 WILL TRANSMIT 256 BYTES.
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DATAPTR = $CE ;POINTER TO THE BYTES TO BE TRANSMITTED NOW
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;-------------------------------------------------------------------------
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AN0OFF = $C058 ;APPLE ADDRESSES THAT CONTROL ANNUNCIATOR OUTPUTS
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AN0ON = $C059 ;PROGRAM REFERNCES ARE RELATIVE TO AN0
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;AN1OFF = $C05A
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;AN1ON = $C05B
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;AN2OFF = $C05C
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;AN2ON = $C05D
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;AN3OFF = $C05E
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;AN3ON = $C05F
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;-------------------------------------------------------------------------
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.proc main
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;---------------------------------------------------------------------------
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START:
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JMP INIT ;MAIN ENTRY POINT - INITIALIZES ANNUNCIATORS
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SENDFP:
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LDA #$90 ;ENTRY POINT FOR APPLESOFT: POKE BYTE AND CALL
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SENDONE:
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JMP XMITONE ;ENTRY POINT FOR TRANSMITTING ONE BYTE FROM ACCUM
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SENDMSG:
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JMP XMITMSG ;ENTRY POINT FOR TRANSMITTING A MIDI MESSAGE
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ALLNOFF:
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JMP QUIET ;TURN ALL NOTES OFF
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TEST1:
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JMP TESTMSG1 ;SEND TEST MESSAGE 1 - C MAJOR CHORD ON
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TEST2:
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JMP TESTMSG2 ;SEND TEST MESSAGE 2 - C MAJOR CHORD OFF
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CHNGANNC:
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JMP CHGANNC ;RECONFIGURE PROGRAM TO USE ANNUNCIATOR NUMBER IN NEXT BYTE
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ANNC2USE:
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.byte $00 ;ONLY LEAST SIGNIFICANT 2 BITS ARE USED
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NEGLOGIC:
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.byte $00 ;SET TO 1 TO USE NEGATIVE LOGIC, OTHERWISE LEAVE 0 FOR POSITIVE LOGIC (DEFAULT). DO NOT USE ANY OTHER VALUES!
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;---------------------------------------------------------------------------
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MAJVER: .byte $01 ;BYTES USED TO TRACK VERSION OF RELEASED EXECUTABLES
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MINVER: .byte $02 ;NIBBLES ARE USED FOR THE VERSION NUMBER ($0102 = VERSION 1.0.2)
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ASAVE: .byte $00 ;SAVE AREA FOR ACCUMULATOR
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SAVENBYT: .byte $00 ;SAVE AREA FOR NUMBYTES
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;---------------------------------------------------------------------------
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INIT: LDA NEGLOGIC
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AND #$FE
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BEQ OK2INIT
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BRK ;ABEND IF NEGLOGIC NOT 0 OR 1
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OK2INIT:
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LDA #<AN0ON ;MODIFY BIT INSTRUCTION BELOW - FLIP LEAST SIGNIFICANT BIT IF NEGATIVE LOGIC
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EOR NEGLOGIC
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STA INITANNC+1
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INITANNC:
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BIT AN0ON
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RTS
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;---------------------------------------------------------------------------
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; CRITICAL TIMING SECTION BELOW MUST NOT CROSS A PAGE BOUNDARY
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;---------------------------------------------------------------------------
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XMITBITS:
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PHP ;SAVE CURRENT INTERRUPT STATUS
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SEI ;MASK INTERRUPTS DURING CRITICAL TIMING SECTION
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STRTBIT:
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BIT AN0OFF ;4 CYCLES - TRANSMIT START BIT - ALWAYS LOW
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JSR DELAY22 ;6+22
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BIT0:
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BIT AN0OFF ;4
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JSR DELAY22 ;6+22
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BIT1:
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BIT AN0OFF ;4
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JSR DELAY22 ;6+22
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BIT2:
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BIT AN0OFF ;4
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JSR DELAY22 ;6+22
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BIT3:
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BIT AN0OFF ;4
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JSR DELAY22 ;6+22
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BIT4:
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BIT AN0OFF ;4
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JSR DELAY22 ;6+22
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BIT5:
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BIT AN0OFF ;4
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JSR DELAY22 ;6+22
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BIT6:
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BIT AN0OFF ;4
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JSR DELAY22 ;6+22
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BIT7:
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BIT AN0OFF ;4
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JSR DELAY22 ;6+22
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STOPBIT:
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BIT AN0ON ;4 ;TRANSMIT STOP BIT - ALWAYS HIGH
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JSR DELAY22 ;6+22
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PLP ;4 ;RESTORE SAVED INTERRUPT STATUS
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RTS ;TOTAL TIME INTERRUPTS DISABLED: 324 MICROSECONDS
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;-----------------------------------------------------------------------
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DELAY22:
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NOP ;WAIT 22 CYCLES
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NOP
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NOP
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NOP
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NOP
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NOP
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NOP
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NOP
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RTS
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;---------------------------------------------------------------------------
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XMITMSG:
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LDA NUMBYTES ;SAVE NUMBER OF BYTES
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STA SAVENBYT ;BECAUSE WE WILL CLOBBER IT
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LDY #$00 ;Y WILL BE AN INDEX INTO THE DATA AREA
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XMITLOOP:
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LDA (DATAPTR),Y ;GET A DATA BYTE
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JSR XMITONE
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INY ;POINT TO NEXT BYTE
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DEC NUMBYTES ;DECREMENT COUNTER
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LDA NUMBYTES ;CHECK IF ZERO
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BNE XMITLOOP ;LOOP UNTIL DONE SENDING ALL BYTES
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LDA SAVENBYT
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STA NUMBYTES ;RESTORE ORIGINAL VALUE OF NUMBYTES
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RTS
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;---------------------------------------------------------------------------
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XMITONE:
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STA ASAVE ;ABEND IF NEGLOGIC NOT 0 OR 1
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LDA NEGLOGIC
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AND #$FE
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BEQ OK2XMIT
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LDA ASAVE
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BRK
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OK2XMIT:
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TXA ;SAVE X AND A ON STACK IN CASE THIS CODE GETS INTERRUPTED
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PHA
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LDA ASAVE
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PHA
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;
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ASL A ;SHIFT BIT INTO CARRY
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TAX ;SAVE CURRENT IMAGE OF DATA BYTE
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LDA #$00 ;ZERO OUT ACCUMULATOR FOR ADD
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MOD1: ADC #<AN0OFF ;ADD CARRY TO ANNUNCIATOR ADDRESS
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EOR NEGLOGIC ;FLIP ADDRESSES IF USING NEGATIVE LOGIC
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STA BIT7+1 ;MODIFY THE XMITBITS SUBROUTINE
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TXA ;RESTORE ACCUMULATOR
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;
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ASL A ;SHIFT BIT INTO CARRY
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TAX ;SAVE CURRENT IMAGE OF DATA BYTE
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LDA #$00 ;ZERO OUT ACCUMULATOR FOR ADD
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MOD2: ADC #<AN0OFF ;ADD CARRY TO ANNUNCIATOR ADDRESS
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EOR NEGLOGIC ;FLIP ADDRESSES IF USING NEGATIVE LOGIC
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STA BIT6+1 ;MODIFY THE XMITBITS SUBROUTINE
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TXA ;RESTORE ACCUMULATOR
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;
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ASL A ;SHIFT BIT INTO CARRY
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TAX ;SAVE CURRENT IMAGE OF DATA BYTE
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LDA #$00 ;ZERO OUT ACCUMULATOR FOR ADD
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MOD3: ADC #<AN0OFF ;ADD CARRY TO ANNUNCIATOR ADDRESS
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EOR NEGLOGIC ;FLIP ADDRESSES IF USING NEGATIVE LOGIC
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STA BIT5+1 ;MODIFY THE XMITBITS SUBROUTINE
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TXA ;RESTORE ACCUMULATOR
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;
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ASL A ;SHIFT BIT INTO CARRY
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TAX ;SAVE CURRENT IMAGE OF DATA BYTE
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LDA #$00 ;ZERO OUT ACCUMULATOR FOR ADD
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MOD4: ADC #<AN0OFF ;ADD CARRY TO ANNUNCIATOR ADDRESS
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EOR NEGLOGIC ;FLIP ADDRESSES IF USING NEGATIVE LOGIC
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STA BIT4+1 ;MODIFY THE XMITBITS SUBROUTINE
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TXA ;RESTORE ACCUMULATOR
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;
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ASL A ;SHIFT BIT INTO CARRY
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TAX ;SAVE CURRENT IMAGE OF DATA BYTE
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LDA #$00 ;ZERO OUT ACCUMULATOR FOR ADD
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MOD5: ADC #<AN0OFF ;ADD CARRY TO ANNUNCIATOR ADDRESS
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EOR NEGLOGIC ;FLIP ADDRESSES IF USING NEGATIVE LOGIC
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STA BIT3+1 ;MODIFY THE XMITBITS SUBROUTINE
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TXA ;RESTORE ACCUMULATOR
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;
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ASL A ;SHIFT BIT INTO CARRY
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TAX ;SAVE CURRENT IMAGE OF DATA BYTE
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LDA #$00 ;ZERO OUT ACCUMULATOR FOR ADD
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MOD6: ADC #<AN0OFF ;ADD CARRY TO ANNUNCIATOR ADDRESS
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EOR NEGLOGIC ;FLIP ADDRESSES IF USING NEGATIVE LOGIC
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STA BIT2+1 ;MODIFY THE XMITBITS SUBROUTINE
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TXA ;RESTORE ACCUMULATOR
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;
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ASL A ;SHIFT BIT INTO CARRY
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TAX ;SAVE CURRENT IMAGE OF DATA BYTE
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LDA #$00 ;ZERO OUT ACCUMULATOR FOR ADD
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MOD7: ADC #<AN0OFF ;ADD CARRY TO ANNUNCIATOR ADDRESS
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EOR NEGLOGIC ;FLIP ADDRESSES IF USING NEGATIVE LOGIC
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STA BIT1+1 ;MODIFY THE XMITBITS SUBROUTINE
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TXA ;RESTORE ACCUMULATOR
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;
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ASL A ;SHIFT BIT INTO CARRY
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TAX ;SAVE CURRENT IMAGE OF DATA BYTE
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LDA #$00 ;ZERO OUT ACCUMULATOR FOR ADD
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MOD8: ADC #<AN0OFF ;ADD CARRY TO ANNUNCIATOR ADDRESS
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EOR NEGLOGIC ;FLIP ADDRESSES IF USING NEGATIVE LOGIC
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STA BIT0+1 ;MODIFY THE XMITBITS SUBROUTINE
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TXA ;RESTORE ACCUMULATOR
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;
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MOD9: LDA #<AN0OFF ;FLIP ANNUNCIATOR ADDRESSES OF START AND STOP BITS IF USING NEGATIVE LOGIC
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EOR NEGLOGIC
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STA STRTBIT+1
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;
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MOD10: LDA #<AN0ON
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EOR NEGLOGIC
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STA STOPBIT+1
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;
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JSR XMITBITS ;SEND THE BYTE OUT
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PLA ;RESTORE A AND X
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STA ASAVE
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PLA
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TAX
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LDA ASAVE
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RTS
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;-----------------------------------------------------------------------
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TESTMSG1:
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LDA #7
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STA NUMBYTES
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LDA #<TESTDAT1
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STA DATAPTR
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LDA #>TESTDAT1
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STA DATAPTR+1
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JSR SENDMSG
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RTS
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;-----------------------------------------------------------------------
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TESTMSG2:
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LDA #7
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STA NUMBYTES
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LDA #<TESTDAT2
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STA DATAPTR
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LDA #>TESTDAT2
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STA DATAPTR+1
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JSR SENDMSG
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RTS
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;-----------------------------------------------------------------------
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QUIET:
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LDA #$90
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STA NUMBYTES
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LDA #<QUIETMSG
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STA DATAPTR
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LDA #>QUIETMSG
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STA DATAPTR+1
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JSR SENDMSG
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RTS
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;-----------------------------------------------------------------------
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CHGANNC:
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LDA ANNC2USE
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AND #$03 ;KEEP ONLY 2 LEAST SIGNIFICANT BITS
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ASL ;MULTIPLY BY 2
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PHA ;SAVE THIS VALUE FOR EACH MOD BEING DONE BELOW
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CLC
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ADC #<AN0OFF ;MODIFY LOW BYTE OF EACH ANNUNCIATOR ADDRESS IN CODE ABOVE
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STA MOD1+1
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;
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PLA ;GET VALUE TO ADD
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PHA ;SAVE IT AGAIN
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CLC
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ADC #<AN0OFF
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STA MOD2+1
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;
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PLA ;GET VALUE TO ADD
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PHA ;SAVE IT AGAIN
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CLC
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ADC #<AN0OFF
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STA MOD3+1
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;
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PLA ;GET VALUE TO ADD
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PHA ;SAVE IT AGAIN
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CLC
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ADC #<AN0OFF
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STA MOD4+1
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;
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PLA ;GET VALUE TO ADD
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PHA ;SAVE IT AGAIN
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CLC
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ADC #<AN0OFF
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STA MOD5+1
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;
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PLA ;GET VALUE TO ADD
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PHA ;SAVE IT AGAIN
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CLC
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ADC #<AN0OFF
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STA MOD6+1
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;
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PLA ;GET VALUE TO ADD
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PHA ;SAVE IT AGAIN
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CLC
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ADC #<AN0OFF
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STA MOD7+1
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;
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PLA ;GET VALUE TO ADD
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PHA ;SAVE IT AGAIN
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CLC
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ADC #<AN0OFF
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STA MOD8+1
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;
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PLA ;GET VALUE TO ADD
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PHA ;SAVE IT AGAIN
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CLC
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ADC #<AN0OFF ;START BIT IS ALWAYS LOW
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STA MOD9+1
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;
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PLA ;GET VALUE TO ADD
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PHA ;SAVE IT AGAIN
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CLC
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ADC #<AN0ON ;STOP BIT IS ALWAYS HIGH
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STA MOD10+1
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;
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PLA ;GET VALUE TO ADD
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CLC
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ADC #<AN0ON ;INITIALIZE MIDI BY SENDING HIGH "CARRIER" BIT
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STA OK2INIT+1
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JMP INIT ;TURN ON THE NEWLY SELECTED ANNUNCIATOR
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;-----------------------------------------------------------------------
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TESTDAT1:
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.byte $90,$3C,$40,$40,$40,$43,$40
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TESTDAT2:
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.byte $90,$3C,$00,$40,$00,$43,$00
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QUIETMSG:
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.byte $B0,$78,$00,$B0,$79,$00,$B0,$7B,$00
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.byte $B1,$78,$00,$B1,$79,$00,$B1,$7B,$00
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.byte $B2,$78,$00,$B2,$79,$00,$B2,$7B,$00
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.byte $B3,$78,$00,$B3,$79,$00,$B3,$7B,$00
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.byte $B4,$78,$00,$B4,$79,$00,$B4,$7B,$00
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.byte $B5,$78,$00,$B5,$79,$00,$B5,$7B,$00
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.byte $B6,$78,$00,$B6,$79,$00,$B6,$7B,$00
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.byte $B7,$78,$00,$B7,$79,$00,$B7,$7B,$00
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.byte $B8,$78,$00,$B8,$79,$00,$B8,$7B,$00
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.byte $B9,$78,$00,$B9,$79,$00,$B9,$7B,$00
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.byte $BA,$78,$00,$BA,$79,$00,$BA,$7B,$00
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.byte $BB,$78,$00,$BB,$79,$00,$BB,$7B,$00
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.byte $BC,$78,$00,$BC,$79,$00,$BC,$7B,$00
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.byte $BD,$78,$00,$BD,$79,$00,$BD,$7B,$00
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.byte $BE,$78,$00,$BE,$79,$00,$BE,$7B,$00
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.byte $BF,$78,$00,$BF,$79,$00,$BF,$7B,$00
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;----------------
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; END OF PROGRAM
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;----------------
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.endproc
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