Working character output, non working return to home

pat80-io-devices/composite-pal-adapter/software/avr-assembly/character_generator.asm

@@ -9,8 +9,8 @@
 .equ LINE_COLUMNS = 52	; number of columns (characters or chunks) per line
 
 ; Draws character in register A to the screen at current coords (Y)
-; @param A (r0) ascii code to display
+; @param r16 (HIGH_ACCUM) ascii code to display
-; @modifies r0 (A), r1, r2, r3, r16 (HIGH_ACCUM), Y, Z
+; @modifies r0 (A), r1, r2, r3, r16 (HIGH_ACCUM), r17, Y, Z
 draw_char:
 	; Glyph's first byte is at:
 	; glyph_pointer = font_starting_mem_pos + (ascii_code * number_of_bytes_per_font)
@@ -22,13 +22,13 @@ draw_char:
 	mov r3, YH
 
 	; Load first glyph position on Z
-	ldi ZH, high(FONT)
+	ldi ZH, high(FONT<<1)
-	ldi ZL, low(FONT)
+	ldi ZL, low(FONT<<1)
-	; Obtain offset multiplying ascii_code * number_of_bytes_per_fontr1
+	; Obtain offset multiplying ascii_code * number_of_bytes_per_font
-	ldi HIGH_ACCUM, FONT_HEIGHT
+	ldi r17, FONT_HEIGHT
-	mul A, HIGH_ACCUM	; result overwrites r0 and r1!
+	mul HIGH_ACCUM, r17	; result overwrites r0 and r1!
 	; 16-bit addition between gliph's first byte position and offset (and store result in Z)
-	add ZL, A
+	add ZL, r0
 	adc ZH, r1
 	; Z contain our glyph's first byte position: draw it
 	; The drawing consist of FONT_HEIGHT cycles. Every glyph byte is placed on its own line
@@ -49,3 +49,11 @@ draw_char:
 	mov YH, r3
 	adiw YH:YL,1	; just increment pre-char-drawing-saved chunk cursor position by 1
 	ret
+
+; Sets the cursor to 0,0 and clears fine position
+cursor_pos_home:
+	; Set Y to framebuffer start
+	ldi YH, high(FRAMEBUFFER)
+	ldi YL, low(FRAMEBUFFER)
+	clr POS_FINE
+	ret

pat80-io-devices/composite-pal-adapter/software/avr-assembly/communication.asm

@@ -31,10 +31,3 @@ comm_init:
 		brne comm_wait_byte	; if not 0, repeat h_picture_loop
         jmp comm_init ; filled all memory: reset framebuffer position
 
-; Sets the cursor to 0,0 and clears fine position
-cursor_pos_home:
-	; Set Y to framebuffer start
-	ldi YH, high(FRAMEBUFFER<<1)
-	ldi YL, low(FRAMEBUFFER<<1)
-	clr POS_FINE
-	ret

pat80-io-devices/composite-pal-adapter/software/avr-assembly/main.asm

@@ -68,29 +68,61 @@ main:
 	ldi	HIGH_ACCUM, 0x00
 	out DDRB, HIGH_ACCUM			; set port as input (used as data bus)
 
+	; clear ram
+	;*** Load data into ram ***
+	; Set X to 0x0100
+	ldi r27, high(FRAMEBUFFER)
+	ldi r26, low(FRAMEBUFFER)
+	load_mem_loop:
+		clr r17
+		st X+, r17
+		; if reached the last framebuffer byte, exit cycle
+		cpi r27, 0b00111110
+		brne load_mem_loop	; if not 0, repeat h_picture_loop
+		cpi r26, 0b11000000
+		brne load_mem_loop	; if not 0, repeat h_picture_loop
+
 	; test draw character routine
-	ser r17
+	;call cursor_pos_home
-	test_draw_loop:
+	ldi HIGH_ACCUM, 'P'
-		ldi r16, 'P'
-		mov A, HIGH_ACCUM
 	call draw_char
 	ldi HIGH_ACCUM, 'A'
-		mov A, HIGH_ACCUM
 	call draw_char
 	ldi HIGH_ACCUM, 'T'
-		mov A, HIGH_ACCUM
 	call draw_char
 	ldi HIGH_ACCUM, '8'
-		mov A, HIGH_ACCUM
 	call draw_char
 	ldi HIGH_ACCUM, '0'
-		mov A, HIGH_ACCUM
 	call draw_char
 	ldi HIGH_ACCUM, ' '
-		mov A, HIGH_ACCUM
 	call draw_char
-		dec r17
+	ldi HIGH_ACCUM, 'H'
-		breq test_draw_loop
+	call draw_char
+	ldi HIGH_ACCUM, 'o'
+	call draw_char
+	ldi HIGH_ACCUM, 'm'
+	call draw_char
+	ldi HIGH_ACCUM, 'e'
+	call draw_char
+	ldi HIGH_ACCUM, ' '
+	call draw_char
+	ldi HIGH_ACCUM, 'c'
+	call draw_char
+	ldi HIGH_ACCUM, 'o'
+	call draw_char
+	ldi HIGH_ACCUM, 'm'
+	call draw_char
+	ldi HIGH_ACCUM, 'p'
+	call draw_char
+	ldi HIGH_ACCUM, 'u'
+	call draw_char
+	ldi HIGH_ACCUM, 't'
+	call draw_char
+	ldi HIGH_ACCUM, 'e'
+	call draw_char
+	ldi HIGH_ACCUM, 'r'
+	call draw_char
+
 
 
 	; *** timer setup (use 16-bit counter TC1) ***
@@ -109,7 +141,7 @@ main:
 	; Timer setup completed.
 
 	; Wait for data (it never exits)
-	jmp comm_init
+	;jmp comm_init
 
 	forever:
 		jmp forever