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-rw-r--r--keyboards/deltasplit75/i2c.c324
1 files changed, 162 insertions, 162 deletions
diff --git a/keyboards/deltasplit75/i2c.c b/keyboards/deltasplit75/i2c.c
index af806c75b..084c890c4 100644
--- a/keyboards/deltasplit75/i2c.c
+++ b/keyboards/deltasplit75/i2c.c
@@ -1,162 +1,162 @@
-#include <util/twi.h>
-#include <avr/io.h>
-#include <stdlib.h>
-#include <avr/interrupt.h>
-#include <util/twi.h>
-#include <stdbool.h>
-#include "i2c.h"
-
-#ifdef USE_I2C
-
-// Limits the amount of we wait for any one i2c transaction.
-// Since were running SCL line 100kHz (=> 10μs/bit), and each transactions is
-// 9 bits, a single transaction will take around 90μs to complete.
-//
-// (F_CPU/SCL_CLOCK) => # of μC cycles to transfer a bit
-// poll loop takes at least 8 clock cycles to execute
-#define I2C_LOOP_TIMEOUT (9+1)*(F_CPU/SCL_CLOCK)/8
-
-#define BUFFER_POS_INC() (slave_buffer_pos = (slave_buffer_pos+1)%SLAVE_BUFFER_SIZE)
-
-volatile uint8_t i2c_slave_buffer[SLAVE_BUFFER_SIZE];
-
-static volatile uint8_t slave_buffer_pos;
-static volatile bool slave_has_register_set = false;
-
-// Wait for an i2c operation to finish
-inline static
-void i2c_delay(void) {
- uint16_t lim = 0;
- while(!(TWCR & (1<<TWINT)) && lim < I2C_LOOP_TIMEOUT)
- lim++;
-
- // easier way, but will wait slightly longer
- // _delay_us(100);
-}
-
-// Setup twi to run at 100kHz
-void i2c_master_init(void) {
- // no prescaler
- TWSR = 0;
- // Set TWI clock frequency to SCL_CLOCK. Need TWBR>10.
- // Check datasheets for more info.
- TWBR = ((F_CPU/SCL_CLOCK)-16)/2;
-}
-
-// Start a transaction with the given i2c slave address. The direction of the
-// transfer is set with I2C_READ and I2C_WRITE.
-// returns: 0 => success
-// 1 => error
-uint8_t i2c_master_start(uint8_t address) {
- TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTA);
-
- i2c_delay();
-
- // check that we started successfully
- if ( (TW_STATUS != TW_START) && (TW_STATUS != TW_REP_START))
- return 1;
-
- TWDR = address;
- TWCR = (1<<TWINT) | (1<<TWEN);
-
- i2c_delay();
-
- if ( (TW_STATUS != TW_MT_SLA_ACK) && (TW_STATUS != TW_MR_SLA_ACK) )
- return 1; // slave did not acknowledge
- else
- return 0; // success
-}
-
-
-// Finish the i2c transaction.
-void i2c_master_stop(void) {
- TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
-
- uint16_t lim = 0;
- while(!(TWCR & (1<<TWSTO)) && lim < I2C_LOOP_TIMEOUT)
- lim++;
-}
-
-// Write one byte to the i2c slave.
-// returns 0 => slave ACK
-// 1 => slave NACK
-uint8_t i2c_master_write(uint8_t data) {
- TWDR = data;
- TWCR = (1<<TWINT) | (1<<TWEN);
-
- i2c_delay();
-
- // check if the slave acknowledged us
- return (TW_STATUS == TW_MT_DATA_ACK) ? 0 : 1;
-}
-
-// Read one byte from the i2c slave. If ack=1 the slave is acknowledged,
-// if ack=0 the acknowledge bit is not set.
-// returns: byte read from i2c device
-uint8_t i2c_master_read(int ack) {
- TWCR = (1<<TWINT) | (1<<TWEN) | (ack<<TWEA);
-
- i2c_delay();
- return TWDR;
-}
-
-void i2c_reset_state(void) {
- TWCR = 0;
-}
-
-void i2c_slave_init(uint8_t address) {
- TWAR = address << 0; // slave i2c address
- // TWEN - twi enable
- // TWEA - enable address acknowledgement
- // TWINT - twi interrupt flag
- // TWIE - enable the twi interrupt
- TWCR = (1<<TWIE) | (1<<TWEA) | (1<<TWINT) | (1<<TWEN);
-}
-
-ISR(TWI_vect);
-
-ISR(TWI_vect) {
- uint8_t ack = 1;
- switch(TW_STATUS) {
- case TW_SR_SLA_ACK:
- // this device has been addressed as a slave receiver
- slave_has_register_set = false;
- break;
-
- case TW_SR_DATA_ACK:
- // this device has received data as a slave receiver
- // The first byte that we receive in this transaction sets the location
- // of the read/write location of the slaves memory that it exposes over
- // i2c. After that, bytes will be written at slave_buffer_pos, incrementing
- // slave_buffer_pos after each write.
- if(!slave_has_register_set) {
- slave_buffer_pos = TWDR;
- // don't acknowledge the master if this memory loctaion is out of bounds
- if ( slave_buffer_pos >= SLAVE_BUFFER_SIZE ) {
- ack = 0;
- slave_buffer_pos = 0;
- }
- slave_has_register_set = true;
- } else {
- i2c_slave_buffer[slave_buffer_pos] = TWDR;
- BUFFER_POS_INC();
- }
- break;
-
- case TW_ST_SLA_ACK:
- case TW_ST_DATA_ACK:
- // master has addressed this device as a slave transmitter and is
- // requesting data.
- TWDR = i2c_slave_buffer[slave_buffer_pos];
- BUFFER_POS_INC();
- break;
-
- case TW_BUS_ERROR: // something went wrong, reset twi state
- TWCR = 0;
- default:
- break;
- }
- // Reset everything, so we are ready for the next TWI interrupt
- TWCR |= (1<<TWIE) | (1<<TWINT) | (ack<<TWEA) | (1<<TWEN);
-}
-#endif
+#include <util/twi.h>
+#include <avr/io.h>
+#include <stdlib.h>
+#include <avr/interrupt.h>
+#include <util/twi.h>
+#include <stdbool.h>
+#include "i2c.h"
+
+#ifdef USE_I2C
+
+// Limits the amount of we wait for any one i2c transaction.
+// Since were running SCL line 100kHz (=> 10μs/bit), and each transactions is
+// 9 bits, a single transaction will take around 90μs to complete.
+//
+// (F_CPU/SCL_CLOCK) => # of μC cycles to transfer a bit
+// poll loop takes at least 8 clock cycles to execute
+#define I2C_LOOP_TIMEOUT (9+1)*(F_CPU/SCL_CLOCK)/8
+
+#define BUFFER_POS_INC() (slave_buffer_pos = (slave_buffer_pos+1)%SLAVE_BUFFER_SIZE)
+
+volatile uint8_t i2c_slave_buffer[SLAVE_BUFFER_SIZE];
+
+static volatile uint8_t slave_buffer_pos;
+static volatile bool slave_has_register_set = false;
+
+// Wait for an i2c operation to finish
+inline static
+void i2c_delay(void) {
+ uint16_t lim = 0;
+ while(!(TWCR & (1<<TWINT)) && lim < I2C_LOOP_TIMEOUT)
+ lim++;
+
+ // easier way, but will wait slightly longer
+ // _delay_us(100);
+}
+
+// Setup twi to run at 100kHz
+void i2c_master_init(void) {
+ // no prescaler
+ TWSR = 0;
+ // Set TWI clock frequency to SCL_CLOCK. Need TWBR>10.
+ // Check datasheets for more info.
+ TWBR = ((F_CPU/SCL_CLOCK)-16)/2;
+}
+
+// Start a transaction with the given i2c slave address. The direction of the
+// transfer is set with I2C_READ and I2C_WRITE.
+// returns: 0 => success
+// 1 => error
+uint8_t i2c_master_start(uint8_t address) {
+ TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTA);
+
+ i2c_delay();
+
+ // check that we started successfully
+ if ( (TW_STATUS != TW_START) && (TW_STATUS != TW_REP_START))
+ return 1;
+
+ TWDR = address;
+ TWCR = (1<<TWINT) | (1<<TWEN);
+
+ i2c_delay();
+
+ if ( (TW_STATUS != TW_MT_SLA_ACK) && (TW_STATUS != TW_MR_SLA_ACK) )
+ return 1; // slave did not acknowledge
+ else
+ return 0; // success
+}
+
+
+// Finish the i2c transaction.
+void i2c_master_stop(void) {
+ TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
+
+ uint16_t lim = 0;
+ while(!(TWCR & (1<<TWSTO)) && lim < I2C_LOOP_TIMEOUT)
+ lim++;
+}
+
+// Write one byte to the i2c slave.
+// returns 0 => slave ACK
+// 1 => slave NACK
+uint8_t i2c_master_write(uint8_t data) {
+ TWDR = data;
+ TWCR = (1<<TWINT) | (1<<TWEN);
+
+ i2c_delay();
+
+ // check if the slave acknowledged us
+ return (TW_STATUS == TW_MT_DATA_ACK) ? 0 : 1;
+}
+
+// Read one byte from the i2c slave. If ack=1 the slave is acknowledged,
+// if ack=0 the acknowledge bit is not set.
+// returns: byte read from i2c device
+uint8_t i2c_master_read(int ack) {
+ TWCR = (1<<TWINT) | (1<<TWEN) | (ack<<TWEA);
+
+ i2c_delay();
+ return TWDR;
+}
+
+void i2c_reset_state(void) {
+ TWCR = 0;
+}
+
+void i2c_slave_init(uint8_t address) {
+ TWAR = address << 0; // slave i2c address
+ // TWEN - twi enable
+ // TWEA - enable address acknowledgement
+ // TWINT - twi interrupt flag
+ // TWIE - enable the twi interrupt
+ TWCR = (1<<TWIE) | (1<<TWEA) | (1<<TWINT) | (1<<TWEN);
+}
+
+ISR(TWI_vect);
+
+ISR(TWI_vect) {
+ uint8_t ack = 1;
+ switch(TW_STATUS) {
+ case TW_SR_SLA_ACK:
+ // this device has been addressed as a slave receiver
+ slave_has_register_set = false;
+ break;
+
+ case TW_SR_DATA_ACK:
+ // this device has received data as a slave receiver
+ // The first byte that we receive in this transaction sets the location
+ // of the read/write location of the slaves memory that it exposes over
+ // i2c. After that, bytes will be written at slave_buffer_pos, incrementing
+ // slave_buffer_pos after each write.
+ if(!slave_has_register_set) {
+ slave_buffer_pos = TWDR;
+ // don't acknowledge the master if this memory loctaion is out of bounds
+ if ( slave_buffer_pos >= SLAVE_BUFFER_SIZE ) {
+ ack = 0;
+ slave_buffer_pos = 0;
+ }
+ slave_has_register_set = true;
+ } else {
+ i2c_slave_buffer[slave_buffer_pos] = TWDR;
+ BUFFER_POS_INC();
+ }
+ break;
+
+ case TW_ST_SLA_ACK:
+ case TW_ST_DATA_ACK:
+ // master has addressed this device as a slave transmitter and is
+ // requesting data.
+ TWDR = i2c_slave_buffer[slave_buffer_pos];
+ BUFFER_POS_INC();
+ break;
+
+ case TW_BUS_ERROR: // something went wrong, reset twi state
+ TWCR = 0;
+ default:
+ break;
+ }
+ // Reset everything, so we are ready for the next TWI interrupt
+ TWCR |= (1<<TWIE) | (1<<TWINT) | (ack<<TWEA) | (1<<TWEN);
+}
+#endif
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