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2 changed files with 34 additions and 27 deletions

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@ -1,13 +1,13 @@
;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
;;This program reads a data stream from the joystick port and saves it in memory.
;;The datastream format is as sutch:
;; This program reads a data stream from the joystick port and saves it in memory.
;; The datastream format is as sutch:
;;
;;############################################
;; 16-bit byte-length (big endian) | data
;;############################################
;; ############################################
;; 16-bit byte-length (big endian) | data
;; ############################################
;; The data comes from CTRL2 bit 0 and the clock is at bit 1
;; The data comes from CTRL1 bit 0 and the clock is at bit 1
;; The stream starts when the clock is pulled high, after that comes a
;; 16-bit big endian number that matches the byte-lenght of the data that will get sent.
@ -21,41 +21,44 @@
;; More documentation on the Joystick port can be found here: https://www.c64-wiki.com/wiki/Joystick
CLKMASK = %00000010
CTRL2 = $DC00
progdest = $fe
CLKMASK = %00000010
CTRL1 = $DC01
.org $80d
coldstart: ;; Draw a dollar sign on screen to show that program has loaded
coldstart: ;; Draw an at sign on screen to show that program has loaded
lda #$0
sta $400
waitstart: ;; Wait until joystick 1 has been pulled forwards to start this program
lda $dc01
and #$01
sta progdest
lda #$c0
sta progdest+1
waitstart: ;; Wait until joystick 2 has been pulled down to start the program
lda $dc00
and #$02
bne waitstart
;; Change boarder colour for debuging
lda #$00
;; Change border colour for debugging
lda #$03
sta $d020
teststart:
jsr check_for_load_start ; Check if start_bit is correct
bcs @error ; Idk why C=1 ask john
bcs @error ; The routine sets carry in the event of an error
beq teststart
@doneforever:
jmp $c000 ; starts the program?
jmp $c000
@error:
lda #1
sta $0400 ;lets store 1 att this address for debuging purposes
rts
check_for_load_start:
lda #CLKMASK
bit CTRL2
bne start ; branch if Z ==0 <--> CTRL2 and CLKMASK ==0 <---> CTRL2 bit 2 == 0
bit CTRL1
bne start
lda #$00
rts
start:
sei
;; change boarder collor for debuging purposes
;; change border color for debugging purposes
ldx #$02
stx $d020
ldy #$00
@ -64,13 +67,13 @@ start:
wait_for_bit_start:
lda #CLKMASK
@loop:
bit CTRL2
bit CTRL1
beq @loop
lda #CLKMASK
bit CTRL2
bit CTRL1
beq error
lda CTRL2
lda CTRL1
lsr
ror BYTE
@ -109,15 +112,19 @@ wait_for_bit_start:
jmp done
@notdone:
new_byte:
;; BYTE is the byte beaing read from the stream. The bits are shifted from the left
;; When we shift out this 1 in BYTE bellow we save the BYTE to memory.
;; BYTE is the byte being read from the stream. The bits are shifted from the left
;; When we shift out this 1 in BYTE below we save the BYTE to memory.
lda #%10000000
sta BYTE
wait_for_bit_end:
lda #CLKMASK
@loop:
bit CTRL2
bit CTRL1
bne @loop
;; Debug show the clock is low
lda #$00
sta $d020
jmp wait_for_bit_start
done:
@ -134,6 +141,5 @@ error:
BYTE = $400
LEN = $402
progdest = $fe
stop: .word $0000
loaded: .byte 0

View file

@ -222,6 +222,7 @@
output-filepath))))
(defun send-data-to-c64 (data)
(declare (type vector data))
(with-open-file (stream "/dev/ttyACM0"
:direction :io
:element-type '(unsigned-byte 8)