Add initial firmware for EPROM

Firmware/Driver.lst

@@ -1,4 +1,4 @@
-ca65 V2.18 - Ubuntu 2.18-1
+ca65 V2.19 - Git 59c58ac
 Main file   : Driver.asm
 Current file: Driver.asm
 

Firmware/Firmware.asm

@@ -0,0 +1,196 @@
+;ProDOS Zero Page
+Command = $42 ;ProDOS Command
+Unit = $43 ;ProDOS unit (SDDD0000)
+BufferLo = $44
+BufferHi = $45
+BlockLo = $46
+BlockHi = $47
+
+; ProDOS Error Codes
+IOError = $27
+NoDevice = $28
+WriteProtect = $2B
+
+SlotDrive = $50
+InputByte = $c08e
+OutputByte = $c08d
+ReadBlockCommand = $01
+WriteBlockCommand = $02
+NibbleStorage = $1d
+
+ .org STARTSLOT
+;ID bytes for booting and drive detection
+ cpx #$20    ;ID bytes for ProDOS and the
+ cpx #$00    ; Apple Autostart ROM
+ cpx #$03    ;
+ cpx #$3C    ;this one for older II's
+
+;load first two blocks and execute to boot
+Boot:
+ lda     #$01    ;set read command
+ sta     Command
+ 
+ jsr $ff58
+ tsx
+ lda $0100,x
+ asl
+ asl
+ asl
+ asl
+ sta $2b
+ sta Unit 
+ tax
+
+ lda     #$00    ;block 0
+ sta     BlockLo
+ sta     BlockHi
+ sta     BufferLo   ;buffer at $800
+ lda     #$08
+ sta     BufferHi
+ jsr     Driver  ;get the block
+
+; lda     #$00    ;block 1
+; sta     BlockLo
+; sta     BlockHi
+; sta     BufferLo   ;buffer at $A00
+; lda     #$0A
+; sta     BufferHi
+; jsr     Driver   ;get the block
+
+; ldx     #sdrive ;set up for slot n
+ jmp     $801    ;execute the block
+
+;;
+; ProDOS Driver code
+; First check that this is the right drive
+Driver: 
+ ldx Unit
+ lda Command; Check which command is being requested
+ beq GetStatus ;0 = Status command
+ cmp #ReadBlockCommand
+ beq ReadBlock
+ cmp #WriteBlockCommand
+ beq WriteBlock
+ sec ;set carry as we don't support any other commands
+ lda #$53 ;Invalid parameter error
+ rts
+
+; ProDOS Status Command Handler
+GetStatus: 
+ ldx #$ff ;low byte number of blocks 
+ ldy #$ff ;high byte number of blocks
+ lda #$0 ;zero accumulator and clear carry for success
+ clc
+ rts
+
+; ProDOS Read Block Command
+ReadBlock: 
+ lda #ReadBlockCommand
+ jsr SendByte
+ lda BlockLo
+ jsr SendByte
+ lda BlockHi
+ jsr SendByte
+ ldy #$0
+ jsr read256
+ inc BufferHi
+ jsr read256
+ dec BufferHi
+ lda #$0 ;zero accumulator and clear carry for success
+ clc
+ rts
+
+read256: 
+ jsr GetByte
+ sta (BufferLo),y
+ iny
+ bne read256
+ rts 
+ 
+; ProDOS Write Block Command
+WriteBlock:
+ lda #WriteBlockCommand
+ jsr SendByte
+ lda BlockLo
+ jsr SendByte
+ lda BlockHi
+ jsr SendByte
+ ldy #$0
+ jsr write256
+ inc BufferHi
+ jsr write256
+ dec BufferHi
+ lda #$0 ;zero accumulator and clear carry for success
+ clc
+ rts
+
+write256:
+ lda (BufferLo),y
+ jsr SendByte
+ iny
+ bne write256
+ rts
+
+SendByte:
+ pha
+ lsr
+ lsr
+ lsr
+ lsr
+ jsr SendNibble
+ pla
+ jsr SendNibble
+ rts
+
+SendNibble:
+ and #$0F
+ ora #$70 ;Write bit low
+ pha 
+waitWrite: 
+ lda InputByte,x
+ asl ;Second highest bit goes low when ready
+ bmi waitWrite
+ pla
+ sta OutputByte,x
+finishWrite:
+ lda InputByte,x
+ asl
+ bpl finishWrite
+ lda #$FF
+ sta OutputByte,x
+ rts
+
+GetByte:
+ jsr GetNibble
+ asl
+ asl
+ asl
+ asl
+ sta NibbleStorage 
+ jsr GetNibble
+ and #$0f
+ ora NibbleStorage
+ rts
+
+GetNibble:
+ lda #$b0 ;set read flag low
+ sta OutputByte,x
+waitRead:
+ lda InputByte,x
+ bmi waitRead
+ ora #$f0 ;set all flags high
+ sta OutputByte,x
+ pha
+finishRead:
+ lda InputByte,x
+ bpl finishRead
+ pla
+end:
+ rts
+
+.repeat	251-<end
+.byte 0
+.endrepeat
+.byte      0,0     ;0000 blocks = check status
+.byte      3       ;bit 0=read 1=status
+.byte     Driver&$00FF ;low byte of entry

Firmware/driver_assemble.sh

@@ -1,3 +1,11 @@
 #!/bin/sh
 ca65 Driver.asm --listing Driver.lst
 ld65 Driver.o -o Driver.bin -t none
+ca65 Firmware.asm -D STARTSLOT=\$c100 -o Slot1.o
+ca65 Firmware.asm -D STARTSLOT=\$c200 -o Slot2.o
+ca65 Firmware.asm -D STARTSLOT=\$c300 -o Slot3.o
+ca65 Firmware.asm -D STARTSLOT=\$c400 -o Slot4.o
+ca65 Firmware.asm -D STARTSLOT=\$c500 -o Slot5.o
+ca65 Firmware.asm -D STARTSLOT=\$c600 -o Slot6.o
+ca65 Firmware.asm -D STARTSLOT=\$c700 -o Slot7.o
+ld65 Slot1.o Slot2.o Slot3.o Slot4.o Slot6.o Slot6.o Slot7.o -o Firmware.bin -t none