4 files changed, 114 insertions, 142 deletions

diff --git a/drivers/avr/i2c_master.c b/drivers/avr/i2c_master.c
index 4e76e2e7c..47c6f8e6c 100755
--- a/drivers/avr/i2c_master.c
+++ b/drivers/avr/i2c_master.c
@@ -15,15 +15,15 @@
 void i2c_init(void)
 {
   TWSR = 0;     /* no prescaler */
-        TWBR = (uint8_t)TWBR_val;
+  TWBR = (uint8_t)TWBR_val;
 }
 
 i2c_status_t i2c_start(uint8_t address, uint16_t timeout)
 {
-        // reset TWI control register
-        TWCR = 0;
-        // transmit START condition
-        TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
+  // reset TWI control register
+  TWCR = 0;
+  // transmit START condition
+  TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
 
   uint16_t timeout_timer = timer_read();
   while( !(TWCR & (1<<TWINT)) ) {
@@ -32,13 +32,13 @@ i2c_status_t i2c_start(uint8_t address, uint16_t timeout)
     }
   }
 
-        // check if the start condition was successfully transmitted
-        if(((TW_STATUS & 0xF8) != TW_START) && ((TW_STATUS & 0xF8) != TW_REP_START)){ return I2C_STATUS_ERROR; }
+  // check if the start condition was successfully transmitted
+  if(((TW_STATUS & 0xF8) != TW_START) && ((TW_STATUS & 0xF8) != TW_REP_START)){ return I2C_STATUS_ERROR; }
 
-        // load slave address into data register
-        TWDR = address;
-        // start transmission of address
-        TWCR = (1<<TWINT) | (1<<TWEN);
+  // load slave address into data register
+  TWDR = address;
+  // start transmission of address
+  TWCR = (1<<TWINT) | (1<<TWEN);
 
   timeout_timer = timer_read();
   while( !(TWCR & (1<<TWINT)) ) {
@@ -47,19 +47,19 @@ i2c_status_t i2c_start(uint8_t address, uint16_t timeout)
     }
   }
 
-        // 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 I2C_STATUS_ERROR;
+  // 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 I2C_STATUS_ERROR;
 
-        return I2C_STATUS_SUCCESS;
+  return I2C_STATUS_SUCCESS;
 }
 
 i2c_status_t i2c_write(uint8_t data, uint16_t timeout)
 {
-        // load data into data register
-        TWDR = data;
-        // start transmission of data
-        TWCR = (1<<TWINT) | (1<<TWEN);
+  // load data into data register
+  TWDR = data;
+  // start transmission of data
+  TWCR = (1<<TWINT) | (1<<TWEN);
 
   uint16_t timeout_timer = timer_read();
   while( !(TWCR & (1<<TWINT)) ) {
@@ -68,16 +68,16 @@ i2c_status_t i2c_write(uint8_t data, uint16_t timeout)
     }
   }
 
-        if( (TW_STATUS & 0xF8) != TW_MT_DATA_ACK ){ return I2C_STATUS_ERROR; }
+  if( (TW_STATUS & 0xF8) != TW_MT_DATA_ACK ){ return I2C_STATUS_ERROR; }
 
-        return I2C_STATUS_SUCCESS;
+  return I2C_STATUS_SUCCESS;
 }
 
 int16_t i2c_read_ack(uint16_t timeout)
 {
 
-        // start TWI module and acknowledge data after reception
-        TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
+  // start TWI module and acknowledge data after reception
+  TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
 
   uint16_t timeout_timer = timer_read();
   while( !(TWCR & (1<<TWINT)) ) {
@@ -86,15 +86,15 @@ int16_t i2c_read_ack(uint16_t timeout)
     }
   }
 
-        // return received data from TWDR
-        return TWDR;
+  // return received data from TWDR
+  return TWDR;
 }
 
 int16_t i2c_read_nack(uint16_t timeout)
 {
 
-        // start receiving without acknowledging reception
-        TWCR = (1<<TWINT) | (1<<TWEN);
+  // start receiving without acknowledging reception
+  TWCR = (1<<TWINT) | (1<<TWEN);
 
   uint16_t timeout_timer = timer_read();
   while( !(TWCR & (1<<TWINT)) ) {
@@ -103,39 +103,39 @@ int16_t i2c_read_nack(uint16_t timeout)
     }
   }
 
-        // return received data from TWDR
-        return TWDR;
+  // return received data from TWDR
+  return TWDR;
 }
 
 i2c_status_t i2c_transmit(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout)
 {
   i2c_status_t status = i2c_start(address | I2C_WRITE, timeout);
-        if (status) return status;
+  if (status) return status;
 
-        for (uint16_t i = 0; i < length; i++) {
-                status = i2c_write(data[i], timeout);
+  for (uint16_t i = 0; i < length; i++) {
+    status = i2c_write(data[i], timeout);
     if (status) return status;
-        }
+  }
 
-        status = i2c_stop(timeout);
+  status = i2c_stop(timeout);
   if (status) return status;
 
-        return I2C_STATUS_SUCCESS;
+  return I2C_STATUS_SUCCESS;
 }
 
 i2c_status_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout)
 {
   i2c_status_t status = i2c_start(address | I2C_READ, timeout);
-        if (status) return status;
+  if (status) return status;
 
-        for (uint16_t i = 0; i < (length-1); i++) {
+  for (uint16_t i = 0; i < (length-1); i++) {
     status = i2c_read_ack(timeout);
     if (status >= 0) {
       data[i] = status;
     } else {
       return status;
     }
-        }
+  }
 
   status = i2c_read_nack(timeout);
   if (status >= 0 ) {
@@ -147,47 +147,47 @@ i2c_status_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16
   status = i2c_stop(timeout);
   if (status) return status;
 
-        return I2C_STATUS_SUCCESS;
+  return I2C_STATUS_SUCCESS;
 }
 
 i2c_status_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout)
 {
   i2c_status_t status = i2c_start(devaddr | 0x00, timeout);
-        if (status) return status;
+  if (status) return status;
 
-        status = i2c_write(regaddr, timeout);
+  status = i2c_write(regaddr, timeout);
   if (status) return status;
 
-        for (uint16_t i = 0; i < length; i++) {
+  for (uint16_t i = 0; i < length; i++) {
     status = i2c_write(data[i], timeout);
-                if (status) return status;
-        }
+    if (status) return status;
+  }
 
-        status = i2c_stop(timeout);
+  status = i2c_stop(timeout);
   if (status) return status;
 
-        return I2C_STATUS_SUCCESS;
+  return I2C_STATUS_SUCCESS;
 }
 
 i2c_status_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout)
 {
   i2c_status_t status = i2c_start(devaddr, timeout);
-        if (status) return status;
+  if (status) return status;
 
   status = i2c_write(regaddr, timeout);
   if (status) return status;
 
   status = i2c_start(devaddr | 0x01, timeout);
-        if (status) return status;
+  if (status) return status;
 
-        for (uint16_t i = 0; i < (length-1); i++) {
-                status = i2c_read_ack(timeout);
+  for (uint16_t i = 0; i < (length-1); i++) {
+    status = i2c_read_ack(timeout);
     if (status >= 0) {
       data[i] = status;
     } else {
       return status;
     }
-        }
+  }
 
   status = i2c_read_nack(timeout);
   if (status >= 0 ) {
@@ -199,13 +199,13 @@ i2c_status_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16
   status = i2c_stop(timeout);
   if (status) return status;
 
-        return I2C_STATUS_SUCCESS;
+  return I2C_STATUS_SUCCESS;
 }
 
 i2c_status_t i2c_stop(uint16_t timeout)
 {
-        // transmit STOP condition
-        TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
+  // transmit STOP condition
+  TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
 
   uint16_t timeout_timer = timer_read();
   while(TWCR & (1<<TWSTO)) {
@@ -215,4 +215,4 @@ i2c_status_t i2c_stop(uint16_t timeout)
   }
 
   return I2C_STATUS_SUCCESS;
-}
+}
\ No newline at end of file
diff --git a/drivers/avr/i2c_master.h b/drivers/avr/i2c_master.h
index cf93680be..89c64599c 100755
--- a/drivers/avr/i2c_master.h
+++ b/drivers/avr/i2c_master.h
@@ -28,4 +28,4 @@ i2c_status_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint1
 i2c_status_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout);
 i2c_status_t i2c_stop(uint16_t timeout);
 
-#endif // I2C_MASTER_H
+#endif // I2C_MASTER_H
\ No newline at end of file
diff --git a/drivers/avr/i2c_slave.c b/drivers/avr/i2c_slave.c
index 3edf85b12..27696ca01 100755
--- a/drivers/avr/i2c_slave.c
+++ b/drivers/avr/i2c_slave.c
@@ -5,96 +5,64 @@
 #include <avr/io.h>
 #include <util/twi.h>
 #include <avr/interrupt.h>
+#include <stdbool.h>
 
 #include "i2c_slave.h"
 
 void i2c_init(uint8_t address){
-        // load address into TWI address register
-        TWAR = (address << 1);
-        // set the TWCR to enable address matching and enable TWI, clear TWINT, enable TWI interrupt
-        TWCR = (1<<TWIE) | (1<<TWEA) | (1<<TWINT) | (1<<TWEN);
+    // load address into TWI address register
+    TWAR = (address << 1);
+    // set the TWCR to enable address matching and enable TWI, clear TWINT, enable TWI interrupt
+    TWCR = (1 << TWIE) | (1 << TWEA) | (1 << TWINT) | (1 << TWEN);
 }
 
 void i2c_stop(void){
-        // clear acknowledge and enable bits
-        TWCR &= ~( (1<<TWEA) | (1<<TWEN) );
+    // clear acknowledge and enable bits
+    TWCR &= ~((1 << TWEA) | (1 << TWEN));
 }
 
 ISR(TWI_vect){
-        
-        // temporary stores the received data
-        uint8_t data;
-        
-        // own address has been acknowledged
-        if( (TWSR & 0xF8) == TW_SR_SLA_ACK ){  
-                buffer_address = 0xFF;
-                // clear TWI interrupt flag, prepare to receive next byte and acknowledge
-                TWCR |= (1<<TWIE) | (1<<TWINT) | (1<<TWEA) | (1<<TWEN); 
-        }
-        else if( (TWSR & 0xF8) == TW_SR_DATA_ACK ){ // data has been received in slave receiver mode
-                
-                // save the received byte inside data 
-                data = TWDR;
-                
-                // check wether an address has already been transmitted or not
-                if(buffer_address == 0xFF){
-                        
-                        buffer_address = data; 
-                        
-                        // clear TWI interrupt flag, prepare to receive next byte and acknowledge
-                        TWCR |= (1<<TWIE) | (1<<TWINT) | (1<<TWEA) | (1<<TWEN); 
-                }
-                else{ // if a databyte has already been received
-                        
-                        // store the data at the current address
-                        rxbuffer[buffer_address] = data;
-                        
-                        // increment the buffer address
-                        buffer_address++;
-                        
-                        // if there is still enough space inside the buffer
-                        if(buffer_address < 0xFF){
-                                // clear TWI interrupt flag, prepare to receive next byte and acknowledge
-                                TWCR |= (1<<TWIE) | (1<<TWINT) | (1<<TWEA) | (1<<TWEN); 
-                        }
-                        else{
-                                // Don't acknowledge
-                                TWCR &= ~(1<<TWEA); 
-                                // clear TWI interrupt flag, prepare to receive last byte.
-                                TWCR |= (1<<TWIE) | (1<<TWINT) | (1<<TWEN); 
-                        }
-                }
-        }
-        else if( (TWSR & 0xF8) == TW_ST_DATA_ACK ){ // device has been addressed to be a transmitter
-                
-                // copy data from TWDR to the temporary memory
-                data = TWDR;
-                
-                // if no buffer read address has been sent yet
-                if( buffer_address == 0xFF ){
-                        buffer_address = data;
-                }
-                
-                // copy the specified buffer address into the TWDR register for transmission
-                TWDR = txbuffer[buffer_address];
-                // increment buffer read address
-                buffer_address++;
-                
-                // if there is another buffer address that can be sent
-                if(buffer_address < 0xFF){
-                        // clear TWI interrupt flag, prepare to send next byte and receive acknowledge
-                        TWCR |= (1<<TWIE) | (1<<TWINT) | (1<<TWEA) | (1<<TWEN); 
-                }
-                else{
-                        // Don't acknowledge
-                        TWCR &= ~(1<<TWEA); 
-                        // clear TWI interrupt flag, prepare to receive last byte.
-                        TWCR |= (1<<TWIE) | (1<<TWINT) | (1<<TWEN); 
-                }
-                
-        }
-        else{
-                // if none of the above apply prepare TWI to be addressed again
-                TWCR |= (1<<TWIE) | (1<<TWEA) | (1<<TWEN);
-        } 
-}
+    uint8_t ack = 1;
+    // temporary stores the received data
+    //uint8_t data;
+    
+    switch(TW_STATUS){
+        case TW_SR_SLA_ACK:
+            // The device is now a slave receiver
+            slave_has_register_set = false;
+            break;
+
+        case TW_SR_DATA_ACK:
+            // This device is a slave receiver and has received data
+            // First byte is the location then the bytes will be writen in buffer with auto-incriment
+            if(!slave_has_register_set){
+                buffer_address = TWDR;
+
+                if (buffer_address >= RX_BUFFER_SIZE){ // address out of bounds dont ack
+                    ack = 0;
+                    buffer_address = 0;
+                }
+                slave_has_register_set = true; // address has been receaved now fill in buffer
+            } else {
+                rxbuffer[buffer_address] = TWDR;
+                buffer_address++;
+            }
+            break;
+
+        case TW_ST_SLA_ACK:
+        case TW_ST_DATA_ACK:
+            // This device is a slave transmitter and master has requested data
+            TWDR = txbuffer[buffer_address];
+            buffer_address++;
+            break;
+
+        case TW_BUS_ERROR:
+            // We got an error, reset i2c
+            TWCR = 0;
+        default:
+            break;
+    }
+
+    // Reset i2c state mahcine to be ready for next interrupt
+    TWCR |= (1 << TWIE) | (1 << TWINT) | (ack << TWEA) | (1 << TWEN);
+}
\ No newline at end of file
diff --git a/drivers/avr/i2c_slave.h b/drivers/avr/i2c_slave.h
index 3fda7f8c0..1c3b9ecc0 100755
--- a/drivers/avr/i2c_slave.h
+++ b/drivers/avr/i2c_slave.h
@@ -8,12 +8,16 @@
 #ifndef I2C_SLAVE_H
 #define I2C_SLAVE_H
 
+#define TX_BUFFER_SIZE 30
+#define RX_BUFFER_SIZE 30
+
 volatile uint8_t buffer_address;
-volatile uint8_t txbuffer[0xFF];
-volatile uint8_t rxbuffer[0xFF];
+static volatile bool slave_has_register_set = false;
+volatile uint8_t txbuffer[TX_BUFFER_SIZE];
+volatile uint8_t rxbuffer[RX_BUFFER_SIZE];
 
 void i2c_init(uint8_t address);
 void i2c_stop(void);
 ISR(TWI_vect);
 
-#endif // I2C_SLAVE_H
+#endif // I2C_SLAVE_H
\ No newline at end of file