640x480 and 800x480 monochrome now working

Required diverging libdvi a little further from the original, sorry

Readme.md

@@ -22,6 +22,13 @@ generated during the Pico SDK build process, is provided here for Arduino
 build to work. If any changes are made in dvi_serialiser.pio (either here
 or by bringing in updates from upstream code), this header will need to be
 regenerated.
+- extern "C" around most function defs, to be linkable with C++ (Arduino).
+- A couple compile-time constants have been changed to run-time configurable
+because some color and resolution things aren't known until a constructor is
+called: dvi_vertical_repeat and dvi_monochrome_tmds.
+- DVI_1BPP_BIT_REVERSE is set '1' by default. This might affect some examples
+built with the Pico SDK (moon, bad_apple), but could be fixed by changing the
+compile definitions in CMakeLists.txt in those app subdirectories.
 
 All files from the PicoDVI repo are kept even if not used in this build
 (e.g. apps and assets directories, among others) so same repo can still be

examples/1bit_single_buffer/1bit_single_buffer.ino

@@ -0,0 +1,20 @@
+// 1-bit Adafruit_GFX-compatible framebuffer for PicoDVI.
+
+#include <PicoDVI.h>
+
+//DVIGFX1 display(640, 480, dvi_timing_640x480p_60hz, VREG_VOLTAGE_1_30, pimoroni_demo_hdmi_cfg);
+DVIGFX1 display(800, 480, dvi_timing_800x480p_60hz, VREG_VOLTAGE_1_30, pimoroni_demo_hdmi_cfg);
+
+void setup() {
+  Serial.begin(115200);
+  //while(!Serial);
+  if (!display.begin()) { // Blink LED if insufficient RAM
+    pinMode(LED_BUILTIN, OUTPUT);
+    for (;;) digitalWrite(LED_BUILTIN, (millis() / 500) & 1);
+  }
+}
+
+void loop() {
+  // Draw random lines
+  display.drawLine(random(display.width()), random(display.height()), random(display.width()), random(display.height()), random(2));
+}

software/libdvi/dvi.c

@@ -7,6 +7,10 @@
 #include "dvi_serialiser.h"
 #include "tmds_encode.h"
 
+// Adafruit PicoDVI fork requires a couple global items run-time configurable:
+uint8_t dvi_vertical_repeat = DVI_VERTICAL_REPEAT;
+bool    dvi_monochrome_tmds = DVI_MONOCHROME_TMDS;
+
 // Time-critical functions pulled into RAM but each in a unique section to
 // allow garbage collection
 #define __dvi_func(f) __not_in_flash_func(f)
@@ -46,11 +50,10 @@ void dvi_init(struct dvi_inst *inst, uint spinlock_tmds_queue, uint spinlock_col
 
 	for (int i = 0; i < DVI_N_TMDS_BUFFERS; ++i) {
 		void *tmdsbuf;
-#if DVI_MONOCHROME_TMDS
-		tmdsbuf = malloc(inst->timing->h_active_pixels / DVI_SYMBOLS_PER_WORD * sizeof(uint32_t));
-#else
-		tmdsbuf = malloc(3 * inst->timing->h_active_pixels / DVI_SYMBOLS_PER_WORD * sizeof(uint32_t));
-#endif
+		if (dvi_monochrome_tmds)
+			tmdsbuf = malloc(inst->timing->h_active_pixels / DVI_SYMBOLS_PER_WORD * sizeof(uint32_t));
+		else
+			tmdsbuf = malloc(3 * inst->timing->h_active_pixels / DVI_SYMBOLS_PER_WORD * sizeof(uint32_t));
 		if (!tmdsbuf)
 			panic("TMDS buffer allocation failed");
 		queue_add_blocking_u32(&inst->q_tmds_free, &tmdsbuf);
@@ -205,7 +208,7 @@ static void __dvi_func(dvi_dma_irq_handler)(struct dvi_inst *inst) {
 		tmdsbuf = NULL;
 	}
 	else if (queue_try_peek_u32(&inst->q_tmds_valid, &tmdsbuf)) {
-		if (inst->timing_state.v_ctr % DVI_VERTICAL_REPEAT == DVI_VERTICAL_REPEAT - 1) {
+		if (inst->timing_state.v_ctr % dvi_vertical_repeat == dvi_vertical_repeat - 1) {
 			queue_remove_blocking_u32(&inst->q_tmds_valid, &tmdsbuf);
 			inst->tmds_buf_release_next = tmdsbuf;
 		}
@@ -213,7 +216,7 @@ static void __dvi_func(dvi_dma_irq_handler)(struct dvi_inst *inst) {
 	else {
 		// No valid scanline was ready (generates solid red scanline)
 		tmdsbuf = NULL;
-		if (inst->timing_state.v_ctr % DVI_VERTICAL_REPEAT == DVI_VERTICAL_REPEAT - 1)
+		if (inst->timing_state.v_ctr % dvi_vertical_repeat == dvi_vertical_repeat - 1)
 			++inst->late_scanline_ctr;
 	}
 
@@ -226,7 +229,7 @@ static void __dvi_func(dvi_dma_irq_handler)(struct dvi_inst *inst) {
 			else {
 				_dvi_load_dma_op(inst->dma_cfg, &inst->dma_list_error);
 			}
-			if (inst->scanline_callback && inst->timing_state.v_ctr % DVI_VERTICAL_REPEAT == DVI_VERTICAL_REPEAT - 1) {
+			if (inst->scanline_callback && inst->timing_state.v_ctr % dvi_vertical_repeat == dvi_vertical_repeat - 1) {
 				inst->scanline_callback();
 			}
 			break;

software/libdvi/dvi_config_defs.h

@@ -118,7 +118,7 @@
 // If 1, reverse the order of pixels within each byte. Order of bytes within
 // each word is still little-endian.
 #ifndef DVI_1BPP_BIT_REVERSE
-#define DVI_1BPP_BIT_REVERSE 0
+#define DVI_1BPP_BIT_REVERSE 1 // Adafruit_GFX GFXcanvas1 requires this 1
 #endif
 
 // ----------------------------------------------------------------------------

software/libdvi/dvi_timing.c

@@ -7,6 +7,8 @@
 //   achievable bit clock from 12 MHz crystal)
 // - Helper functions for generating DMA lists based on these timings
 
+extern bool dvi_monochrome_tmds; // In dvi.c
+
 // Pull into RAM but apply unique section suffix to allow linker GC
 #define __dvi_func(x) __not_in_flash_func(x)
 #define __dvi_const(x) __not_in_flash_func(x)
@@ -312,11 +314,7 @@ void dvi_setup_scanline_for_active(const struct dvi_timing *t, const struct dvi_
 
 void __dvi_func(dvi_update_scanline_data_dma)(const struct dvi_timing *t, const uint32_t *tmdsbuf, struct dvi_scanline_dma_list *l) {
 	for (int i = 0; i < N_TMDS_LANES; ++i) {
-#if DVI_MONOCHROME_TMDS
-		const uint32_t *lane_tmdsbuf = tmdsbuf;
-#else
-		const uint32_t *lane_tmdsbuf = tmdsbuf + i * t->h_active_pixels / DVI_SYMBOLS_PER_WORD;
-#endif
+		const uint32_t *lane_tmdsbuf = dvi_monochrome_tmds ? tmdsbuf : tmdsbuf + i * t->h_active_pixels / DVI_SYMBOLS_PER_WORD;
 		if (i == TMDS_SYNC_LANE)
 			dvi_lane_from_list(l, i)[3].read_addr = lane_tmdsbuf;
 		else

src/PicoDVI.cpp

@@ -47,7 +47,10 @@ static void *gfxptr = NULL; // For C access to active C++ object
 DVIGFX16::DVIGFX16(const uint16_t w, const uint16_t h,
                    const struct dvi_timing &t, vreg_voltage v,
                    const struct dvi_serialiser_cfg &c)
-    : PicoDVI(t, v, c), GFXcanvas16(w, h) {}
+    : PicoDVI(t, v, c), GFXcanvas16(w, h) {
+  dvi_vertical_repeat = 2;
+  dvi_monochrome_tmds = false;
+}
 
 DVIGFX16::~DVIGFX16(void) { gfxptr = NULL; }
 
@@ -102,6 +105,8 @@ DVIGFX8::DVIGFX8(const uint16_t w, const uint16_t h, const struct dvi_timing &t,
                  vreg_voltage v, const struct dvi_serialiser_cfg &c)
     : PicoDVI(t, v, c), GFXcanvas8(w, ((h + 1) & ~1) + 4) {
   HEIGHT = _height = h;
+  dvi_vertical_repeat = 2;
+  dvi_monochrome_tmds = false;
 }
 
 DVIGFX8::~DVIGFX8(void) { gfxptr = NULL; }
@@ -162,6 +167,8 @@ DVIGFX8x2::DVIGFX8x2(const uint16_t w, const uint16_t h,
     : PicoDVI(t, v, c), GFXcanvas8(w, h * 2 + 4) {
   HEIGHT = _height = h;
   buffer_save = buffer;
+  dvi_vertical_repeat = 2;
+  dvi_monochrome_tmds = false;
 }
 
 DVIGFX8x2::~DVIGFX8x2(void) {
@@ -242,7 +249,10 @@ void DVIGFX8x2::swap(bool copy_framebuffer, bool copy_palette) {
 
 DVIGFX1::DVIGFX1(const uint16_t w, const uint16_t h, const struct dvi_timing &t,
                  vreg_voltage v, const struct dvi_serialiser_cfg &c)
-    : PicoDVI(t, v, c), GFXcanvas1(w, h) {}
+    : PicoDVI(t, v, c), GFXcanvas1(w, h) {
+  dvi_vertical_repeat = 1;
+  dvi_monochrome_tmds = true;
+}
 
 DVIGFX1::~DVIGFX1(void) { gfxptr = NULL; }
 

src/PicoDVI.h

@@ -6,6 +6,9 @@
 #include "pico/stdlib.h" // In Pico SDK
 #include <Adafruit_GFX.h>
 
+extern uint8_t dvi_vertical_repeat; // In libdvi/dvi.c
+extern bool dvi_monochrome_tmds;    // In libdvi/dvi.c
+
 class PicoDVI {
 public:
   PicoDVI(const struct dvi_timing &t = dvi_timing_640x480p_60hz,