1 files changed, 162 insertions, 0 deletions
diff --git a/roms/simple_ram_test2.asm b/roms/simple_ram_test2.asm
new file mode 100644
index 0000000..9803056
--- /dev/null
+++ b/roms/simple_ram_test2.asm
@@ -0,0 +1,162 @@
+PORTB = $6000
+PORTA = $6001
+DDRB  = $6002
+DDRA  = $6003
+
+E     = %10000000
+RW    = %01000000
+RS    = %00100000
+
+ .org #$f800
+
+reset:
+ ldx #$FF			; initialize call stack to $1FF
+ txs
+
+ lda #%11111111			; set output on all pins of PORTB
+ sta DDRB
+
+ lda #%11100000			; set output on LCD control pins of PORTA
+ sta DDRA
+
+ lda #%00111000			; set 8-bit, 2-line display, 5x8 font
+ jsr lcd_send_command
+
+ lda #%00001110			; display on, cursor on, no blink
+ jsr lcd_send_command
+
+ lda #%00000001			; clear display
+ jsr lcd_send_command
+
+ lda #%00000010			; return home
+ jsr lcd_send_command
+
+ lda #%00000110			; set entry mode: increment, no shift
+ jsr lcd_send_command
+
+set_memory:
+ ldy #$0
+ ldx #$FF
+set_memory_loop:
+ sty $0, x
+ iny
+ dex
+ bne set_memory_loop
+ 
+test_memory:
+ ldy #$0
+ ldx #$FF
+test_memory_loop:
+ tya
+ pha 
+ lda $0, x
+ cmp $1FF			; stack was empty so Y is now on top of stack
+ bne test_memory_bad
+ pla
+ tay
+ iny
+ dex
+ bne test_memory_loop
+ jmp test_memory_ok
+
+test_memory_bad:
+ ldx #0
+msg_loop_bad:
+ lda message_memory_bad, x
+ beq msg_end_bad
+ jsr lcd_send_data
+ inx
+ jmp msg_loop_bad
+msg_end_bad:
+ jmp finish
+
+test_memory_ok:
+ ldx #0
+msg_loop_ok:
+ lda message_memory_ok, x
+ beq msg_end_ok
+ jsr lcd_send_data
+ inx
+ jmp msg_loop_ok
+msg_end_ok
+
+finish:
+ jmp finish
+
+term:
+ jmp term
+
+lcd_wait:
+ pha
+ lda #%00000000			; port B to all input
+ sta DDRB
+
+lcd_wait_loop:
+ lda #RW
+ sta PORTA
+
+ lda #(RW | E)
+ sta PORTA
+
+ lda PORTB
+ and #%10000000
+ bne lcd_wait_loop
+
+ lda #RW
+ sta PORTA
+ lda #%11111111                 ; port B back to output
+ sta DDRB
+
+ pla
+ rts
+
+lcd_send_command:
+
+ jsr lcd_wait
+
+ sta PORTB
+
+ lda #$0			; clear RS/RW/E
+ sta PORTA
+
+ lda #E				; clear RS/RW, set E, send instruction
+ sta PORTA
+
+ lda #$0			; clear RS/RW/E
+ sta PORTA
+
+ rts
+
+lcd_send_data:
+
+ jsr lcd_wait
+
+ sta PORTB			; data to send to port B
+
+ lda #RS			; clear RW, E, set RS for data
+ sta PORTA
+
+ lda #( E | RS )		; clear RW, set E/RS, send data
+ sta PORTA
+
+ lda #RS			; clear RS, E, keep RS
+ sta PORTA
+
+ rts
+
+nmi:
+ rti
+
+irq:
+ rti
+
+message_memory_bad:
+ .asciiz "mem bad"
+ 
+message_memory_ok:
+ .asciiz "mem ok"
+
+ .org #$fffa
+ .word nmi
+ .word reset
+ .word irq