add highscore display

game-ctrl/eeprom.c

@@ -0,0 +1,75 @@
+#include <stdint.h>
+#include "eeprom.h"
+#include "spi.h"
+
+
+#define MAGIC 0xaffe
+#define HIGHSCORE_ADDR 0x00
+#define DUMMY 0x00
+#define CMD_READ  0b00000011
+#define CMD_WRITE 0b00000010
+#define CMD_WRDI  0b00000100
+#define CMD_WREN  0b00000110
+
+
+typedef union {
+  uint8_t buffer[4];
+  struct {
+    uint16_t magic;
+    uint16_t highScore;
+  } v;
+} eepromBuf_t;
+
+eepromBuf_t buf;
+
+static void writeBuf() {
+  spiSendBegin(e_SPI_EEPROM);
+  spiSendOctet(CMD_WREN);
+  spiSendEnd(e_SPI_EEPROM);
+
+  spiSendBegin(e_SPI_EEPROM);
+  spiSendOctet(CMD_WRITE);
+  spiSendOctet(HIGHSCORE_ADDR);
+  spiSendOctet(buf.buffer[0]);
+  spiSendOctet(buf.buffer[1]);
+  spiSendOctet(buf.buffer[2]);
+  spiSendOctet(buf.buffer[3]);
+  spiSendEnd(e_SPI_EEPROM);
+}
+
+static void readBuf() {
+  spiSendBegin(e_SPI_EEPROM);
+  spiSendOctet(CMD_READ);
+  spiReceiveOctet();
+  spiSendOctet(HIGHSCORE_ADDR);
+  spiReceiveOctet();
+  spiSendOctet(DUMMY);
+  buf.buffer[0] = spiReceiveOctet();
+  spiSendOctet(DUMMY);
+  buf.buffer[1] = spiReceiveOctet();
+  spiSendOctet(DUMMY);
+  buf.buffer[2] = spiReceiveOctet();
+  spiSendOctet(DUMMY);
+  buf.buffer[3] = spiReceiveOctet();
+  spiSendEnd(e_SPI_EEPROM);
+}
+
+void eepromInit() {
+  readBuf();
+
+  if (buf.v.magic != MAGIC) {
+    buf.v.magic = MAGIC;
+    buf.v.highScore = 0;
+    writeBuf();
+  }
+}
+
+uint16_t eepromReadHighScore() {
+  return buf.v.highScore;
+}
+
+void eepromWriteHighScore(uint16_t v) {
+  buf.v.highScore = v;
+  writeBuf();
+}
+