Co-authored-by: Joel Challis <git@zvecr.com>pull/22021/head
@ -1,87 +0,0 @@ | |||||
/* | |||||
Copyright 2017 Balz Guenat | |||||
based on work by Jun Wako <wakojun@gmail.com> | |||||
This program is free software: you can redistribute it and/or modify | |||||
it under the terms of the GNU General Public License as published by | |||||
the Free Software Foundation, either version 2 of the License, or | |||||
(at your option) any later version. | |||||
This program is distributed in the hope that it will be useful, | |||||
but WITHOUT ANY WARRANTY; without even the implied warranty of | |||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |||||
GNU General Public License for more details. | |||||
You should have received a copy of the GNU General Public License | |||||
along with this program. If not, see <http://www.gnu.org/licenses/>. | |||||
*/ | |||||
#include "actuation_point.h" | |||||
#include "i2c.h" | |||||
/////////////////////////////////////////////////////////////////////////////// | |||||
// | |||||
// AD5258 I2C digital potentiometer | |||||
// http://www.analog.com/media/en/technical-documentation/data-sheets/AD5258.pdf | |||||
// | |||||
#define AD5258_ADDR 0b0011000 | |||||
#define AD5258_INST_RDAC 0x00 | |||||
#define AD5258_INST_EEPROM 0x20 | |||||
uint8_t read_rdac(void) { | |||||
// read RDAC register | |||||
i2c_start_write(AD5258_ADDR); | |||||
i2c_master_write(AD5258_INST_RDAC); | |||||
i2c_start_read(AD5258_ADDR); | |||||
uint8_t ret = i2c_master_read(I2C_NACK); | |||||
i2c_master_stop(); | |||||
return ret; | |||||
}; | |||||
uint8_t read_eeprom(void) { | |||||
i2c_start_write(AD5258_ADDR); | |||||
i2c_master_write(AD5258_INST_EEPROM); | |||||
i2c_start_read(AD5258_ADDR); | |||||
uint8_t ret = i2c_master_read(I2C_NACK); | |||||
i2c_master_stop(); | |||||
return ret; | |||||
}; | |||||
void write_rdac(uint8_t rdac) { | |||||
// write RDAC register: | |||||
i2c_start_write(AD5258_ADDR); | |||||
i2c_master_write(AD5258_INST_RDAC); | |||||
i2c_master_write(rdac & 0x3F); | |||||
i2c_master_stop(); | |||||
}; | |||||
void actuation_point_up(void) { | |||||
// write RDAC register: lower value makes actuation point shallow | |||||
uint8_t rdac = read_rdac(); | |||||
if (rdac == 0) | |||||
write_rdac(0); | |||||
else | |||||
write_rdac(rdac-1); | |||||
}; | |||||
void actuation_point_down(void) { | |||||
// write RDAC register: higher value makes actuation point deep | |||||
uint8_t rdac = read_rdac(); | |||||
if (rdac == 63) | |||||
write_rdac(63); | |||||
else | |||||
write_rdac(rdac+1); | |||||
}; | |||||
void adjust_actuation_point(int offset) { | |||||
i2c_master_init(); | |||||
uint8_t rdac = read_eeprom() + offset; | |||||
if (rdac > 63) { // protects from under and overflows | |||||
if (offset > 0) | |||||
write_rdac(63); | |||||
else | |||||
write_rdac(0); | |||||
} else { | |||||
write_rdac(rdac); | |||||
} | |||||
} |
@ -0,0 +1,52 @@ | |||||
/* | |||||
Copyright 2017 Balz Guenat | |||||
based on work by Jun Wako <wakojun@gmail.com> | |||||
This program is free software: you can redistribute it and/or modify | |||||
it under the terms of the GNU General Public License as published by | |||||
the Free Software Foundation, either version 2 of the License, or | |||||
(at your option) any later version. | |||||
This program is distributed in the hope that it will be useful, | |||||
but WITHOUT ANY WARRANTY; without even the implied warranty of | |||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |||||
GNU General Public License for more details. | |||||
You should have received a copy of the GNU General Public License | |||||
along with this program. If not, see <http://www.gnu.org/licenses/>. | |||||
*/ | |||||
#include "ad5258.h" | |||||
#include "i2c_master.h" | |||||
/////////////////////////////////////////////////////////////////////////////// | |||||
// | |||||
// AD5258 I2C digital potentiometer | |||||
// http://www.analog.com/media/en/technical-documentation/data-sheets/AD5258.pdf | |||||
// | |||||
#define AD5258_I2C_ADDRESS 0x18 | |||||
#define AD5258_INST_RDAC 0x00 | |||||
#define AD5258_INST_EEPROM 0x20 | |||||
void ad5258_init(void) { | |||||
i2c_init(); | |||||
} | |||||
uint8_t ad5258_read_rdac(void) { | |||||
// read RDAC register | |||||
uint8_t ret = 0; | |||||
i2c_readReg(AD5258_I2C_ADDRESS, AD5258_INST_RDAC, &ret, 1, 100); | |||||
return ret; | |||||
} | |||||
uint8_t ad5258_read_eeprom(void) { | |||||
uint8_t ret = 0; | |||||
i2c_readReg(AD5258_I2C_ADDRESS, AD5258_INST_EEPROM, &ret, 1, 100); | |||||
return ret; | |||||
} | |||||
void ad5258_write_rdac(uint8_t rdac) { | |||||
// write RDAC register: | |||||
uint8_t data = rdac & 0x3F; | |||||
i2c_writeReg(AD5258_I2C_ADDRESS, AD5258_INST_RDAC, &data, 1, 100); | |||||
} |
@ -0,0 +1,28 @@ | |||||
/* | |||||
Copyright 2017 Balz Guenat | |||||
This program is free software: you can redistribute it and/or modify | |||||
it under the terms of the GNU General Public License as published by | |||||
the Free Software Foundation, either version 2 of the License, or | |||||
(at your option) any later version. | |||||
This program is distributed in the hope that it will be useful, | |||||
but WITHOUT ANY WARRANTY; without even the implied warranty of | |||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |||||
GNU General Public License for more details. | |||||
You should have received a copy of the GNU General Public License | |||||
along with this program. If not, see <http://www.gnu.org/licenses/>. | |||||
*/ | |||||
#pragma once | |||||
#include <stdint.h> | |||||
void ad5258_init(void); | |||||
uint8_t ad5258_read_rdac(void); | |||||
uint8_t ad5258_read_eeprom(void); | |||||
void ad5258_write_rdac(uint8_t rdac); |
@ -1,162 +0,0 @@ | |||||
#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 |
@ -1,46 +0,0 @@ | |||||
#pragma once | |||||
#include <stdint.h> | |||||
#ifndef F_CPU | |||||
#define F_CPU 16000000UL | |||||
#endif | |||||
#define I2C_READ 1 | |||||
#define I2C_WRITE 0 | |||||
#define I2C_ACK 1 | |||||
#define I2C_NACK 0 | |||||
#define SLAVE_BUFFER_SIZE 0x10 | |||||
// i2c SCL clock frequency | |||||
#define SCL_CLOCK 400000L | |||||
extern volatile uint8_t i2c_slave_buffer[SLAVE_BUFFER_SIZE]; | |||||
void i2c_master_init(void); | |||||
uint8_t i2c_master_start(uint8_t address); | |||||
void i2c_master_stop(void); | |||||
uint8_t i2c_master_write(uint8_t data); | |||||
uint8_t i2c_master_read(int); | |||||
void i2c_reset_state(void); | |||||
void i2c_slave_init(uint8_t address); | |||||
static inline unsigned char i2c_start_read(unsigned char addr) { | |||||
return i2c_master_start((addr << 1) | I2C_READ); | |||||
} | |||||
static inline unsigned char i2c_start_write(unsigned char addr) { | |||||
return i2c_master_start((addr << 1) | I2C_WRITE); | |||||
} | |||||
// from SSD1306 scrips | |||||
extern unsigned char i2c_rep_start(unsigned char addr); | |||||
extern void i2c_start_wait(unsigned char addr); | |||||
extern unsigned char i2c_readAck(void); | |||||
extern unsigned char i2c_readNak(void); | |||||
extern unsigned char i2c_read(unsigned char ack); | |||||
#define i2c_read(ack) (ack) ? i2c_readAck() : i2c_readNak(); |
@ -1,87 +0,0 @@ | |||||
/* | |||||
Copyright 2017 Balz Guenat | |||||
based on work by Jun Wako <wakojun@gmail.com> | |||||
This program is free software: you can redistribute it and/or modify | |||||
it under the terms of the GNU General Public License as published by | |||||
the Free Software Foundation, either version 2 of the License, or | |||||
(at your option) any later version. | |||||
This program is distributed in the hope that it will be useful, | |||||
but WITHOUT ANY WARRANTY; without even the implied warranty of | |||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |||||
GNU General Public License for more details. | |||||
You should have received a copy of the GNU General Public License | |||||
along with this program. If not, see <http://www.gnu.org/licenses/>. | |||||
*/ | |||||
#include "actuation_point.h" | |||||
#include "i2c.h" | |||||
/////////////////////////////////////////////////////////////////////////////// | |||||
// | |||||
// AD5258 I2C digital potentiometer | |||||
// http://www.analog.com/media/en/technical-documentation/data-sheets/AD5258.pdf | |||||
// | |||||
#define AD5258_ADDR 0b0011000 | |||||
#define AD5258_INST_RDAC 0x00 | |||||
#define AD5258_INST_EEPROM 0x20 | |||||
uint8_t read_rdac(void) { | |||||
// read RDAC register | |||||
i2c_start_write(AD5258_ADDR); | |||||
i2c_master_write(AD5258_INST_RDAC); | |||||
i2c_start_read(AD5258_ADDR); | |||||
uint8_t ret = i2c_master_read(I2C_NACK); | |||||
i2c_master_stop(); | |||||
return ret; | |||||
}; | |||||
uint8_t read_eeprom(void) { | |||||
i2c_start_write(AD5258_ADDR); | |||||
i2c_master_write(AD5258_INST_EEPROM); | |||||
i2c_start_read(AD5258_ADDR); | |||||
uint8_t ret = i2c_master_read(I2C_NACK); | |||||
i2c_master_stop(); | |||||
return ret; | |||||
}; | |||||
void write_rdac(uint8_t rdac) { | |||||
// write RDAC register: | |||||
i2c_start_write(AD5258_ADDR); | |||||
i2c_master_write(AD5258_INST_RDAC); | |||||
i2c_master_write(rdac & 0x3F); | |||||
i2c_master_stop(); | |||||
}; | |||||
void actuation_point_up(void) { | |||||
// write RDAC register: lower value makes actuation point shallow | |||||
uint8_t rdac = read_rdac(); | |||||
if (rdac == 0) | |||||
write_rdac(0); | |||||
else | |||||
write_rdac(rdac-1); | |||||
}; | |||||
void actuation_point_down(void) { | |||||
// write RDAC register: higher value makes actuation point deep | |||||
uint8_t rdac = read_rdac(); | |||||
if (rdac == 63) | |||||
write_rdac(63); | |||||
else | |||||
write_rdac(rdac+1); | |||||
}; | |||||
void adjust_actuation_point(int offset) { | |||||
i2c_master_init(); | |||||
uint8_t rdac = read_eeprom() + offset; | |||||
if (rdac > 63) { // protects from under and overflows | |||||
if (offset > 0) | |||||
write_rdac(63); | |||||
else | |||||
write_rdac(0); | |||||
} else { | |||||
write_rdac(rdac); | |||||
} | |||||
} |
@ -0,0 +1,52 @@ | |||||
/* | |||||
Copyright 2017 Balz Guenat | |||||
based on work by Jun Wako <wakojun@gmail.com> | |||||
This program is free software: you can redistribute it and/or modify | |||||
it under the terms of the GNU General Public License as published by | |||||
the Free Software Foundation, either version 2 of the License, or | |||||
(at your option) any later version. | |||||
This program is distributed in the hope that it will be useful, | |||||
but WITHOUT ANY WARRANTY; without even the implied warranty of | |||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |||||
GNU General Public License for more details. | |||||
You should have received a copy of the GNU General Public License | |||||
along with this program. If not, see <http://www.gnu.org/licenses/>. | |||||
*/ | |||||
#include "ad5258.h" | |||||
#include "i2c_master.h" | |||||
/////////////////////////////////////////////////////////////////////////////// | |||||
// | |||||
// AD5258 I2C digital potentiometer | |||||
// http://www.analog.com/media/en/technical-documentation/data-sheets/AD5258.pdf | |||||
// | |||||
#define AD5258_I2C_ADDRESS 0x18 | |||||
#define AD5258_INST_RDAC 0x00 | |||||
#define AD5258_INST_EEPROM 0x20 | |||||
void ad5258_init(void) { | |||||
i2c_init(); | |||||
} | |||||
uint8_t ad5258_read_rdac(void) { | |||||
// read RDAC register | |||||
uint8_t ret = 0; | |||||
i2c_readReg(AD5258_I2C_ADDRESS, AD5258_INST_RDAC, &ret, 1, 100); | |||||
return ret; | |||||
} | |||||
uint8_t ad5258_read_eeprom(void) { | |||||
uint8_t ret = 0; | |||||
i2c_readReg(AD5258_I2C_ADDRESS, AD5258_INST_EEPROM, &ret, 1, 100); | |||||
return ret; | |||||
} | |||||
void ad5258_write_rdac(uint8_t rdac) { | |||||
// write RDAC register: | |||||
uint8_t data = rdac & 0x3F; | |||||
i2c_writeReg(AD5258_I2C_ADDRESS, AD5258_INST_RDAC, &data, 1, 100); | |||||
} |
@ -0,0 +1,28 @@ | |||||
/* | |||||
Copyright 2017 Balz Guenat | |||||
This program is free software: you can redistribute it and/or modify | |||||
it under the terms of the GNU General Public License as published by | |||||
the Free Software Foundation, either version 2 of the License, or | |||||
(at your option) any later version. | |||||
This program is distributed in the hope that it will be useful, | |||||
but WITHOUT ANY WARRANTY; without even the implied warranty of | |||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |||||
GNU General Public License for more details. | |||||
You should have received a copy of the GNU General Public License | |||||
along with this program. If not, see <http://www.gnu.org/licenses/>. | |||||
*/ | |||||
#pragma once | |||||
#include <stdint.h> | |||||
void ad5258_init(void); | |||||
uint8_t ad5258_read_rdac(void); | |||||
uint8_t ad5258_read_eeprom(void); | |||||
void ad5258_write_rdac(uint8_t rdac); |
@ -1,162 +0,0 @@ | |||||
#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 |
@ -1,46 +0,0 @@ | |||||
#pragma once | |||||
#include <stdint.h> | |||||
#ifndef F_CPU | |||||
#define F_CPU 16000000UL | |||||
#endif | |||||
#define I2C_READ 1 | |||||
#define I2C_WRITE 0 | |||||
#define I2C_ACK 1 | |||||
#define I2C_NACK 0 | |||||
#define SLAVE_BUFFER_SIZE 0x10 | |||||
// i2c SCL clock frequency | |||||
#define SCL_CLOCK 400000L | |||||
extern volatile uint8_t i2c_slave_buffer[SLAVE_BUFFER_SIZE]; | |||||
void i2c_master_init(void); | |||||
uint8_t i2c_master_start(uint8_t address); | |||||
void i2c_master_stop(void); | |||||
uint8_t i2c_master_write(uint8_t data); | |||||
uint8_t i2c_master_read(int); | |||||
void i2c_reset_state(void); | |||||
void i2c_slave_init(uint8_t address); | |||||
static inline unsigned char i2c_start_read(unsigned char addr) { | |||||
return i2c_master_start((addr << 1) | I2C_READ); | |||||
} | |||||
static inline unsigned char i2c_start_write(unsigned char addr) { | |||||
return i2c_master_start((addr << 1) | I2C_WRITE); | |||||
} | |||||
// from SSD1306 scrips | |||||
extern unsigned char i2c_rep_start(unsigned char addr); | |||||
extern void i2c_start_wait(unsigned char addr); | |||||
extern unsigned char i2c_readAck(void); | |||||
extern unsigned char i2c_readNak(void); | |||||
extern unsigned char i2c_read(unsigned char ack); | |||||
#define i2c_read(ack) (ack) ? i2c_readAck() : i2c_readNak(); |