working on serial syncronization for programming eeprom

1 files changed, 21 insertions, 9 deletions

diff --git a/src/i2c.c b/src/i2c.c
index 25b2d0f..0b1cb90 100644
--- a/src/i2c.c
+++ b/src/i2c.c
@@ -37,7 +37,7 @@
  * 
   */
 
-void error() {}
+void error() {  }
 
 void i2c_init() {
   TWBR = 12;
@@ -48,29 +48,30 @@ void i2c_init() {
 void i2c_start(uint8_t addr, bool rw) {
   TWCR = (_BV(TWSTA) | _BV(TWEN) | _BV(TWINT)); //send start signal
   loop_until_bit_is_set(TWCR, TWINT);
-  if((TWSR & 0xf8) != TW_START) { 
+  if(((TWSR & 0xf8) != (TW_START)) && ((TWSR & 0xf8) != (TW_REP_START))) { 
     #ifdef DEBUG_BUILD
-      printf("Couldn't set start condition?\n");
+      printf("Couldn't set start condition? TWSR: 0x%x\r\n", TWSR & 0xf8);
     #endif
     error();
   }
+  
 
   TWDR = (addr << 1) | rw;
   TWCR = _BV(TWINT) | _BV(TWEN); 
   loop_until_bit_is_set(TWCR, TWINT);
 
-  if((TWSR & 0xf8) != TW_MT_SLA_ACK) { 
+  if(((TWSR & 0xf8) != (TW_MT_SLA_ACK)) && (TWSR & 0xf8) != (TW_MR_SLA_ACK)) { 
     #ifdef DEBUG_BUILD
       printf("unhandled NACK in address transmission\
           TWCR: 0x%x\
-          TWSR: 0x%x\n", TWCR, (TWSR & ~(0b11)));
+          TWSR: 0x%x\r\n", TWCR, (TWSR & ~(0b11)));
     #endif
     error();
   }
 
 }
 
-void i2c_stop() { TWCR = (_BV(TWSTO) | _BV(TWEN) | _BV(TWINT)); }
+void i2c_stop() { TWCR = (_BV(TWSTO) | _BV(TWEN) | _BV(TWINT)); _delay_ms(500); }
 
 void i2c_send(uint8_t byte) {
   TWDR = byte; //fist packet is address 
@@ -81,7 +82,7 @@ void i2c_send(uint8_t byte) {
     #ifdef DEBUG_BUILD
       printf("unhandled NACK in data transmission\
           TWCR: 0x%x\
-          TWSR: 0x%x\n", TWCR, (TWSR & ~(0b11)));
+          TWSR: 0x%x\r\n", TWCR, (TWSR & ~(0b11)));
     #endif
     error();
   }
@@ -89,11 +90,14 @@ void i2c_send(uint8_t byte) {
 
 uint8_t i2c_recv() {
   uint8_t value;
+  TWCR = _BV(TWINT) | _BV(TWEN); 
   loop_until_bit_is_set(TWCR, TWINT);
   value = TWDR;
-  if((TWSR & 0xf8) != TW_MR_SLA_ACK) {
+  //the eeprom supposedly doesn't return an ack here, 
+  //as it should (according to its datasheet), but it still works?
+  if(((TWSR & 0xf8) != TW_MR_DATA_ACK) && ((TWSR & 0xf8) != TW_MR_DATA_NACK)) { 
 #ifdef DEBUG_BUILD
-    printf("Error recieving byte from i2c device\n");
+    printf("Error recieving byte from i2c device: 0x%x\r\n", TWSR & 0xf8);
 #endif
   error();
   }
@@ -128,3 +132,11 @@ void i2c_write_reg_multi(uint8_t device_addr, uint8_t device_reg, size_t len, ui
   for(size_t on_byte = 0; on_byte < len; on_byte++) i2c_send(values[on_byte]);
   i2c_stop();
 }
+
+void i2c_write_reg_addr16(uint8_t device_addr, uint16_t device_reg, uint8_t data) {
+  i2c_start(device_addr, I2C_WRITE);
+  i2c_send((uint8_t)device_reg & 0xff);
+  i2c_send((uint8_t)device_reg >> 8);
+  i2c_send(data);
+  i2c_stop();
+}