include/arch/atmega2560/driver/timer.h

@@ -19,19 +19,16 @@ class Timer {
 
 		inline void setup_khz(uint16_t const frequency) { // 16 MHz base
 			OCR4A = frequency ? 16000 / frequency : 65535;
-			TCCR4A = 0;
-			TCCR4B = _BV(WGM42);
 			prescaler = _BV(CS40);
 		}
-		inline void setup_hz(uint16_t const frequency) { // 16 MHz / 256 == 62.5 kHz base
-			OCR4A = frequency ? 62500 / frequency : 65535;
-			TCCR4A = 0;
-			TCCR4B = _BV(WGM42);
+		inline void setup_hz(uint16_t const frequency) { // 16 MHz / 1024 == 15625 Hz base
+			OCR4A = frequency ? 15625 / frequency : 65535;
 			prescaler = _BV(CS42);
 		}
 		inline void start(unsigned char const interrupt) {
 			TCNT4 = 0;
-			TCCR4B |= prescaler;
+			TCCR4A = 0;
+			TCCR4B = _BV(WGM42) | prescaler;
 			if (interrupt) {
 				TIMSK4 = _BV(OCIE4A);
 			}

src/app/bad-apple-atmega2560-ssd1306/Kconfig

+# Copyright 2020 Birte Kristina Friesel
+#
+# SPDX-License-Identifier: CC0-1.0
+
+prompt "Bad Apple on ATMega2560 + SSD1306 128x32 OLED"
+depends on arch_atmega2560
+depends on meta_driver_timer
+depends on driver_ssd1306 && driver_ssd1306_mode_horizontal
+depends on lib_inflate && lib_inflate_lut
+depends on !loop
+depends on !wakeup

src/app/bad-apple-atmega2560-ssd1306/Makefile.inc

+# vim:ft=make
+#
+# Copyright 2020 Birte Kristina Friesel
+#
+# SPDX-License-Identifier: CC0-1.0

src/app/bad-apple-atmega2560-ssd1306/convert

+#!/bin/sh
+
+# [size=WxH] ./convert.sh <file> -r <frame rate> [additional ffmpeg args]
+
+set -eu
+
+mkdir -p tmp
+
+ffmpeg -i "$@" tmp/frame%4d.png
+
+parallel mogrify -resize "${size:-128x32}" -threshold 50% -- tmp/*.png
+
+echo "#include <avr/pgmspace.h>" > frames.cc
+echo "const unsigned char frame_rate = $3;" >> frames.cc
+./frames-to-cc tmp/*.png >> frames.cc
+
+rm -rf tmp

src/app/bad-apple-atmega2560-ssd1306/frames-to-cc

+#!/usr/bin/env python3
+
+from PIL import Image
+import os
+import sys
+import zlib
+
+buf_w, buf_h = map(int, os.getenv("size", "128x32").split("x"))
+
+
+def load_image(filename):
+    im = Image.open(filename)
+    w, h = im.size
+    buf = [0 for i in range(buf_w * buf_h // 8)]
+    for y in range(min(h, buf_h)):
+        for x in range(min(w, buf_w)):
+            if im.getpixel((x, y)):
+                buf[(y // 8) * buf_w + x] |= 1 << (y % 8)
+    return buf
+
+
+for i in range(1, len(sys.argv) - 2):
+    buf = load_image(sys.argv[i])
+    c_buf = ",".join(map(str, buf))
+    z_buf = zlib.compress(bytes(buf), 9)
+    z_buf = z_buf[2:-4]
+    out_buf = ",".join(map(str, z_buf))
+    print(f"unsigned char const PROGMEM frame{i:04d}[] = {{ {len(z_buf)}, {out_buf} }};")
+
+frames = list()
+for i in range(1, len(sys.argv) - 2):
+    frames.append(f"frame{i:04d}")
+
+prefix = "const unsigned char* const frames[] PROGMEM = {"
+postfix = "};"
+
+print(prefix + ", ".join(frames) + postfix)

src/app/bad-apple-atmega2560-ssd1306/main.cc

+/*
+ * Copyright 2020 Birte Kristina Friesel
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+#include "arch.h"
+#include "driver/gpio.h"
+#include "driver/stdout.h"
+#include "driver/i2c.h"
+#include "driver/ssd1306.h"
+#include "lib/inflate.h"
+
+#include "driver/timer.h"
+volatile unsigned char timer_done = 0;
+
+#include "frames.cc"
+
+/*
+ * fgrep 'PROGMEM frame' frames.cc | while read line; do echo $line | tr -cd , | wc -c; done | sort -n
+ * set buffer size to maximum number + 1.
+ */
+unsigned char deflate_buf[160];
+unsigned char img_buf[(SSD1306_WIDTH * SSD1306_HEIGHT / 8)];
+
+int main(void)
+{
+	unsigned int i = 0, j = 0;
+	unsigned char line, frame_len;
+	unsigned char *frame;
+	arch.setup();
+	gpio.setup();
+	kout.setup();
+	i2c.setup();
+	ssd1306.init();
+
+	timer.setup_hz(frame_rate);
+	timer_done = 0;
+	timer.start(1);
+
+	while (1) {
+		for (i = 0; i < (sizeof(frames) / sizeof(frames[0])); i++) {
+
+			frame = (unsigned char *)pgm_read_ptr(&frames[i]);
+			frame_len = (unsigned char)pgm_read_byte(&frame[0]);
+
+			for (j = 0; j < frame_len; j++) {
+				deflate_buf[j] = (unsigned char)pgm_read_byte(&frame[j+1]);
+			}
+			inflate(deflate_buf, frame_len + 4, img_buf, sizeof(img_buf));
+
+			while (!timer_done) {
+				arch.idle();
+			}
+			timer.stop();
+			timer_done = 0;
+			timer.start(1);
+
+			ssd1306.showImage(img_buf, SSD1306_WIDTH * SSD1306_HEIGHT / 8);
+		}
+	}
+
+	return 0;
+}
+
+ON_TIMER_INTERRUPT_head
+	timer_done = 1;
+ON_TIMER_INTERRUPT_tail