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-rwxr-xr-xdrivers/avr/i2c_master.c149
1 files changed, 149 insertions, 0 deletions
diff --git a/drivers/avr/i2c_master.c b/drivers/avr/i2c_master.c
new file mode 100755
index 0000000000..f4a4bb7b0b
--- /dev/null
+++ b/drivers/avr/i2c_master.c
@@ -0,0 +1,149 @@
+/* Library made by: g4lvanix
+ * Github repository: https://github.com/g4lvanix/I2C-master-lib
+ */
+
+#include <avr/io.h>
+#include <util/twi.h>
+
+#include "i2c_master.h"
+
+#define F_SCL 400000UL // SCL frequency
+#define Prescaler 1
+#define TWBR_val ((((F_CPU / F_SCL) / Prescaler) - 16 ) / 2)
+
+void i2c_init(void)
+{
+ TWBR = (uint8_t)TWBR_val;
+}
+
+uint8_t i2c_start(uint8_t address)
+{
+ // reset TWI control register
+ TWCR = 0;
+ // transmit START condition
+ TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
+ // wait for end of transmission
+ while( !(TWCR & (1<<TWINT)) );
+
+ // check if the start condition was successfully transmitted
+ if((TWSR & 0xF8) != TW_START){ return 1; }
+
+ // load slave address into data register
+ TWDR = address;
+ // start transmission of address
+ TWCR = (1<<TWINT) | (1<<TWEN);
+ // wait for end of transmission
+ while( !(TWCR & (1<<TWINT)) );
+
+ // check if the device has acknowledged the READ / WRITE mode
+ uint8_t twst = TW_STATUS & 0xF8;
+ if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return 1;
+
+ return 0;
+}
+
+uint8_t i2c_write(uint8_t data)
+{
+ // load data into data register
+ TWDR = data;
+ // start transmission of data
+ TWCR = (1<<TWINT) | (1<<TWEN);
+ // wait for end of transmission
+ while( !(TWCR & (1<<TWINT)) );
+
+ if( (TWSR & 0xF8) != TW_MT_DATA_ACK ){ return 1; }
+
+ return 0;
+}
+
+uint8_t i2c_read_ack(void)
+{
+
+ // start TWI module and acknowledge data after reception
+ TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
+ // wait for end of transmission
+ while( !(TWCR & (1<<TWINT)) );
+ // return received data from TWDR
+ return TWDR;
+}
+
+uint8_t i2c_read_nack(void)
+{
+
+ // start receiving without acknowledging reception
+ TWCR = (1<<TWINT) | (1<<TWEN);
+ // wait for end of transmission
+ while( !(TWCR & (1<<TWINT)) );
+ // return received data from TWDR
+ return TWDR;
+}
+
+uint8_t i2c_transmit(uint8_t address, uint8_t* data, uint16_t length)
+{
+ if (i2c_start(address | I2C_WRITE)) return 1;
+
+ for (uint16_t i = 0; i < length; i++)
+ {
+ if (i2c_write(data[i])) return 1;
+ }
+
+ i2c_stop();
+
+ return 0;
+}
+
+uint8_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length)
+{
+ if (i2c_start(address | I2C_READ)) return 1;
+
+ for (uint16_t i = 0; i < (length-1); i++)
+ {
+ data[i] = i2c_read_ack();
+ }
+ data[(length-1)] = i2c_read_nack();
+
+ i2c_stop();
+
+ return 0;
+}
+
+uint8_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length)
+{
+ if (i2c_start(devaddr | 0x00)) return 1;
+
+ i2c_write(regaddr);
+
+ for (uint16_t i = 0; i < length; i++)
+ {
+ if (i2c_write(data[i])) return 1;
+ }
+
+ i2c_stop();
+
+ return 0;
+}
+
+uint8_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length)
+{
+ if (i2c_start(devaddr)) return 1;
+
+ i2c_write(regaddr);
+
+ if (i2c_start(devaddr | 0x01)) return 1;
+
+ for (uint16_t i = 0; i < (length-1); i++)
+ {
+ data[i] = i2c_read_ack();
+ }
+ data[(length-1)] = i2c_read_nack();
+
+ i2c_stop();
+
+ return 0;
+}
+
+void i2c_stop(void)
+{
+ // transmit STOP condition
+ TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
+}