X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=common%2Feeprom.c;fp=common%2Feeprom.c;h=9027ed02fbf2809f35136b5bbd5dfc278dd8371e;hb=9c37d18b9c70fdb70dfec453398c4649e9e57586;hp=0000000000000000000000000000000000000000;hpb=49b6b6ad84ec47b4f9eb9ef131975cc5b72372a2;p=model-railway-devices.git

diff --git a/common/eeprom.c b/common/eeprom.c
new file mode 100644
index 0000000..9027ed0
--- /dev/null
+++ b/common/eeprom.c
@@ -0,0 +1,29 @@
+#include <avr/io.h>
+#include "eeprom.h"
+
+#define BIT(n) (1<<(n))
+
+static void eeprom_wait(void)
+{
+	while(EECR&BIT(EEPE)) ;
+}
+
+void eeprom_write(uint16_t addr, uint8_t data)
+{
+	eeprom_wait();
+	EEARH = addr>>8;
+	EEARL = addr;
+	EEDR = data;
+	EECR = BIT(EEMPE);
+	EECR |= BIT(EEPE);
+	eeprom_wait();
+}
+
+uint8_t eeprom_read(uint16_t addr)
+{
+	eeprom_wait();
+	EEARH = addr>>8;
+	EEARL = addr;
+	EECR = BIT(EERE);
+	return EEDR;
+}