prepare state machine to receive animation messages

4 files changed, 117 insertions, 16 deletions

diff --git a/src/storage.cc b/src/storage.cc
index 4decc27..71265a8 100644
--- a/src/storage.cc
+++ b/src/storage.cc
@@ -46,6 +46,8 @@ void Storage::enable()
 	 */
 	TWSR = 0; // the lower two bits control TWPS
 	TWBR = ((F_CPU / 100000UL) - 16) / 2;
+
+	i2c_read(0, 1, &num_anims);
 }
 
 
@@ -168,3 +170,35 @@ int8_t Storage::i2c_read(uint16_t pos, uint8_t len, uint8_t *data)
 
 	return 0; // TODO proper return code to indicate read/write errors
 }
+
+void Storage::reset()
+{
+	uint8_t data = 0;
+	i2c_write(0, 1, &data);
+	first_free_page = 0;
+}
+
+void Storage::load(uint16_t idx, uint8_t *data)
+{
+	uint8_t page_offset;
+	uint8_t header[2];
+	i2c_read(1 + idx, 1, &page_offset);
+
+	i2c_read(256 + (64 * (uint16_t)page_offset), 2, header);
+	i2c_read(256 + (64 * (uint16_t)page_offset) + 2, (header[0] << 4) + (header[1] >> 4), data);
+}
+
+void Storage::save(uint16_t idx, uint8_t *data)
+{
+	i2c_write(1 + idx, 1, &first_free_page);
+	append(data);
+}
+
+void Storage::append(uint8_t *data)
+{
+	// the header indicates the length of the data, but we really don't care
+	// - it's easier to just write the whole page and skip the trailing
+	// garbage when reading.
+	i2c_write(256 + (64 * (uint16_t)first_free_page), 64, data);
+	first_free_page++;
+}
diff --git a/src/storage.h b/src/storage.h
index 011406d..4336d34 100644
--- a/src/storage.h
+++ b/src/storage.h
@@ -4,6 +4,8 @@
 
 class Storage {
 	private:
+		uint8_t num_anims;
+		uint8_t first_free_page;
 		void i2c_start_write(void);
 		void i2c_start_read(void);
 		void i2c_stop(void);
@@ -13,8 +15,12 @@ class Storage {
 		int8_t i2c_write(uint16_t addr, uint8_t len, uint8_t *data);
 		// TODO "file system" housekeeping (index of first free page)
 	public:
-		Storage() {};
+		Storage() { num_anims = 0xff; first_free_page = 0;};
 		void enable();
+		void reset();
+		void load(uint16_t idx, uint8_t *data);
+		void save(uint16_t idx, uint8_t *data);
+		void append(uint8_t *data);
 		// TODO load / save methods for animations
 };
 
diff --git a/src/system.cc b/src/system.cc
index 537f0b9..bee1791 100644
--- a/src/system.cc
+++ b/src/system.cc
@@ -16,6 +16,7 @@ System rocket;
 extern animation_t ohai;
 
 uint8_t disp_buf[128];
+uint8_t *rx_buf = disp_buf + 64;
 
 void System::initialize()
 {
@@ -35,10 +36,65 @@ void System::initialize()
 	sei();
 }
 
+void System::receive(void)
+{
+	static uint8_t rx_pos = 0;
+	static uint16_t remaining_bytes = 0;
+	uint8_t rx_byte = modem.buffer_get();
+
+	if (rxExpect > PATTERN2) {
+		rx_buf[rx_pos] = modem.buffer_get();
+	}
+
+	switch(rxExpect) {
+		case START1:
+			if (rx_byte == 0x99)
+				rxExpect = START2;
+			break;
+		case START2:
+			if (rx_byte == 0x99)
+				rxExpect = PATTERN1;
+			break;
+		case PATTERN1:
+			if (rx_byte == 0xa9)
+				rxExpect = PATTERN2;
+			break;
+		case PATTERN2:
+			if (rx_byte == 0xa9)
+				rxExpect = HEADER1;
+			break;
+		case HEADER1:
+			rxExpect = HEADER2;
+			break;
+		case HEADER2:
+			rxExpect = META1;
+			break;
+		case META1:
+			rxExpect = META2;
+			break;
+		case META2:
+			rxExpect = DATA;
+			break;
+		case DATA:
+			break;
+	}
+
+	/*
+	if (i == 127) {
+		i = 0;
+	} else if (modem_byte == 0) {
+		if (i > 1) { // workaround for trailing double null bytes
+			ohai.data = disp_buf;
+			ohai.length = i-1;
+			display.show(&ohai);
+		}
+		i = 0;
+	}
+	*/
+}
+
 void System::loop()
 {
-	static uint8_t i = 0;
-	uint8_t modem_byte;
 	// both buttons are pressed
 	if ((PINC & (_BV(PC3) | _BV(PC7))) == 0) {
 		// naptime!
@@ -62,18 +118,7 @@ void System::loop()
 	}
 
 	while (modem.buffer_available()) {
-		modem_byte = modem.buffer_get();
-		disp_buf[i++] = modem_byte;
-		if (i == 127) {
-			i = 0;
-		} else if (modem_byte == 0) {
-			if (i > 1) { // workaround for trailing double null bytes
-				ohai.data = disp_buf;
-				ohai.length = i-1;
-				display.show(&ohai);
-			}
-			i = 0;
-		}
+		receive();
 	}
 
 	display.update();
diff --git a/src/system.h b/src/system.h
index 7c0ab80..a2aad25 100644
--- a/src/system.h
+++ b/src/system.h
@@ -10,8 +10,24 @@ class System {
 	private:
 		uint16_t want_shutdown;
 		void shutdown(void);
+		void receive(void);
+
+		enum RxExpect : uint8_t {
+			START1,
+			START2,
+			PATTERN1,
+			PATTERN2,
+			HEADER1,
+			HEADER2,
+			META1,
+			META2,
+			DATA
+		};
+
+		RxExpect rxExpect;
+
 	public:
-		System() { want_shutdown = 0; };
+		System() { want_shutdown = 0; rxExpect = START1; };
 
 		/**
 		 * Initial MCU setup. Turns off unused peripherals to save power