Fixed kernel audio issue

Author: charliegreen

common.def.h

@@ -29,6 +29,9 @@
 #define R_TXTI r10
 #define R_CLRI r25
 
+;;; TODO: we might be able to save cycles by jumping to a special bit of code for the last tile on
+;;; each scanline and doing extra work between the `out`s
+
 .macro TILE_ROW n,p0,p1,p2,p3,p4,p5
 _tilerow_\n:
 	out	VIDEO_PORT, \p0

tile_generator.py

@@ -5,8 +5,6 @@
 
 TILE_W, TILE_H = 6, 8
 
-# TODO: DON'T KEEP FONT IN RAM, USE LPM TO LOAD IT
-
 # Note: also, only '_' actually uses a pixel on the far left in any of its rows; we might be able to
 # cut down to 5-wide characters that always emit a background pixel on the far left
 
@@ -49,7 +47,7 @@ def load_png(filepath):
         FILENAME = FILEPATH
 
     OUTPUT = OUTPUT_DIR + FILENAME[0:-4] + ".s"
-        
+
     PNG_W_PX, PNG_H_PX, pixels, metadata = load_png(FILEPATH)
     W, H = int(PNG_W_PX/TILE_W), int(PNG_H_PX/TILE_H) # width, height of our image, in tiles
 
@@ -70,7 +68,7 @@ def load_png(filepath):
 
     # for rowi in range(len(unique_rows)):
     #     print("{}:\t{}".format(rowi, unique_rows[rowi]))
-    
+
     with open(OUTPUT, 'w') as f:
         f.write(HEADER.format(FILEPATH))
 

tiles.s

@@ -1,5 +1,5 @@
 #include "common.def.h"
-	
+
 	.section .text
 
 	.global	begin_code_tile_row
@@ -15,7 +15,7 @@ begin_code_tile_row:
 	mul	R_TILE_Y, r16
 	add	YL, r0
 	adc	YH, r1
-	
+
 	ldi	XH, hi8(m96_palette)
 
 	;; ---------------------------------------- load first tile's colors

video.s

@@ -1,18 +1,17 @@
 ;;; ================================================================================
 ;;; Video Mode 96: text-only display with arbitrary color palettes
-;;; 
+;;;
 ;;; Type: 		tile-based
-;;; Cycles/Pixel:	?? TODO
 ;;; Tile Size:		6x8
-;;; Resolution:		?? TODO
-;;; 
+;;; Resolution:		(216x224) 36x28
+;;;
 ;;; Each scanline must total 1820 cycles. There are 524 scanlines total.
-	
+
 #include "common.def.h"
-	
+
 	.global vram		; just global for debugging
 	.global m96_palette
-	
+
 	.section .bss
 vram:		.space VRAM_SIZE
 
@@ -33,7 +32,7 @@ sub_video_mode96:
 	mov	R_FONTL, r16
 	ldi	r16, hi8(m96_font)
 	mov	R_FONTH, r16
-	
+
 	;; pm converts from byte addresses to word addresses (divides by 2)
 	ldi	r16, lo8(pm(m96_rows))
 	mov	R_ROWSL, r16
@@ -58,8 +57,8 @@ render_scanline:
 	;; `rcall` and `lds` both take 2 cycles, so should be 0x64
 	lds	r16, TCNT1L
 	lds	r17, TCNT1H
-	rcall	hsync_pulse	;156 cycles (154 inside hsync_pulse)
 
+	rcall	hsync_pulse	;156 cycles (154 inside hsync_pulse) with AUDIO_OUT_HSYNC_CYCLES=135
 	WAIT	r16, HSYNC_USABLE_CYCLES - AUDIO_OUT_HSYNC_CYCLES
 
 	;; do our code tile setup
@@ -84,12 +83,12 @@ render_scanline:
 	nop
 2:
 	;; -------------------- continue to next line or end of frame, synced to 1820 cycle boundary
-	WAIT	r16, 55
-	
+	WAIT	r16, 41
+
 	;; if we've just drawn the last scanline, be done
 	dec	R_SCANLINE_COUNTER
 	breq	frame_end
-	
+
 	rjmp	render_scanline
 
 frame_end:
@@ -109,5 +108,5 @@ frame_end:
 	;; clear any pending timer int
 	ldi ZL,(1<<OCF1A)
 	sts _SFR_MEM_ADDR(TIFR1),ZL
-	
+
 	ret			; returning from call to sub_video_mode96

videoMode.def.h

@@ -5,7 +5,8 @@
 
 #define VMODE_FUNC sub_video_mode96
 
-#define HSYNC_USABLE_CYCLES 244
+// 258 is the maximum value of AUDIO_OUT_HSYNC_CYCLES, so less means cutting kernel functionality
+#define HSYNC_USABLE_CYCLES 258
 
 #define FONT_TILE_WIDTH  35	// size of a tile row in words
 #define TILE_HEIGHT 8