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-rw-r--r--src/storage.cc28
-rw-r--r--src/storage.h19
2 files changed, 33 insertions, 14 deletions
diff --git a/src/storage.cc b/src/storage.cc
index 4afe1d8..7ee5f4c 100644
--- a/src/storage.cc
+++ b/src/storage.cc
@@ -55,30 +55,42 @@ void Storage::enable()
* Send an I2C (re)start condition and the EEPROM address in read mode. Returns
* after it has been transmitted successfully.
*/
-void Storage::i2c_start_read()
+uint8_t Storage::i2c_start_read()
{
TWCR = _BV(TWINT) | _BV(TWSTA) | _BV(TWEN);
while (!(TWCR & _BV(TWINT)));
+ if (!(TWSR & 0x18)) // 0x08 == START ok, 0x10 == RESTART ok
+ return I2C_START_ERR;
// Note: The R byte ("... | 1") causes the TWI momodule to switch to
// Master Receive mode
TWDR = (I2C_EEPROM_ADDR << 1) | 1;
TWCR = _BV(TWINT) | _BV(TWEN);
while (!(TWCR & _BV(TWINT)));
+ if (TWSR != 0x40) // 0x40 == SLA+R transmitted, ACK receveid
+ return I2C_ADDR_ERR;
+
+ return I2C_OK;
}
/*
* Send an I2C (re)start condition and the EEPROM address in write mode.
* Returns after it has been transmitted successfully.
*/
-void Storage::i2c_start_write()
+uint8_t Storage::i2c_start_write()
{
TWCR = _BV(TWINT) | _BV(TWSTA) | _BV(TWEN);
while (!(TWCR & _BV(TWINT)));
+ if (!(TWSR & 0x18)) // 0x08 == START ok, 0x10 == RESTART ok
+ return I2C_START_ERR;
TWDR = (I2C_EEPROM_ADDR << 1) | 0;
TWCR = _BV(TWINT) | _BV(TWEN);
while (!(TWCR & _BV(TWINT)));
+ if (TWSR != 0x18) // 0x18 == SLA+W transmitted, ACK received
+ return I2C_ADDR_ERR;
+
+ return I2C_OK;
}
/*
@@ -93,8 +105,7 @@ void Storage::i2c_stop()
* Sends len bytes to the EEPROM. Note that this method does NOT
* send I2C start or stop conditions.
*/
-// TODO Everything[tm] (error handling and generic code)
-int8_t Storage::i2c_send(uint8_t len, uint8_t *data)
+uint8_t Storage::i2c_send(uint8_t len, uint8_t *data)
{
uint8_t pos = 0;
@@ -102,6 +113,8 @@ int8_t Storage::i2c_send(uint8_t len, uint8_t *data)
TWDR = data[pos];
TWCR = _BV(TWINT) | _BV(TWEN);
while (!(TWCR & _BV(TWINT)));
+ if (TWSR != 0x28) // 0x28 == byte transmitted, ACK received
+ return pos;
}
return pos + 1;
@@ -111,8 +124,7 @@ int8_t Storage::i2c_send(uint8_t len, uint8_t *data)
* Receives len bytes from the EEPROM into data. Note that this method does
* NOT send I2C start or stop conditions.
*/
-// TODO dito
-int8_t Storage::i2c_receive(uint8_t len, uint8_t *data)
+uint8_t Storage::i2c_receive(uint8_t len, uint8_t *data)
{
uint8_t pos = 0;
@@ -136,7 +148,7 @@ int8_t Storage::i2c_receive(uint8_t len, uint8_t *data)
* Does not check for page boundaries yet.
* Includes a complete I2C transaction.
*/
-int8_t Storage::i2c_write(uint16_t pos, uint8_t len, uint8_t *data)
+uint8_t Storage::i2c_write(uint16_t pos, uint8_t len, uint8_t *data)
{
uint8_t addr_buf[2];
@@ -156,7 +168,7 @@ int8_t Storage::i2c_write(uint16_t pos, uint8_t len, uint8_t *data)
* Does not check for page boundaries yet.
* Includes a complete I2C transaction.
*/
-int8_t Storage::i2c_read(uint16_t pos, uint8_t len, uint8_t *data)
+uint8_t Storage::i2c_read(uint16_t pos, uint8_t len, uint8_t *data)
{
uint8_t addr_buf[2];
addr_buf[0] = pos >> 8;
diff --git a/src/storage.h b/src/storage.h
index fd7b0ad..b2a4dbf 100644
--- a/src/storage.h
+++ b/src/storage.h
@@ -6,13 +6,20 @@ class Storage {
private:
uint8_t num_anims;
uint8_t first_free_page;
- void i2c_start_write(void);
- void i2c_start_read(void);
+ uint8_t i2c_start_write(void);
+ uint8_t i2c_start_read(void);
void i2c_stop(void);
- int8_t i2c_send(uint8_t len, uint8_t *data);
- int8_t i2c_receive(uint8_t len, uint8_t *data);
- int8_t i2c_read(uint16_t addr, uint8_t len, uint8_t *data);
- int8_t i2c_write(uint16_t addr, uint8_t len, uint8_t *data);
+ uint8_t i2c_send(uint8_t len, uint8_t *data);
+ uint8_t i2c_receive(uint8_t len, uint8_t *data);
+ uint8_t i2c_read(uint16_t addr, uint8_t len, uint8_t *data);
+ uint8_t i2c_write(uint16_t addr, uint8_t len, uint8_t *data);
+
+ enum I2CStatus : uint8_t {
+ I2C_OK,
+ I2C_START_ERR,
+ I2C_ADDR_ERR
+ };
+
public:
Storage() { num_anims = 0; first_free_page = 0;};