drivers/avr/i2c_master.c

   1 /*  Copyright (C) 2019 Elia Ritterbusch
   2  +
   3  *  This program is free software: you can redistribute it and/or modify
   4  *  it under the terms of the GNU General Public License as published by
   5  *  the Free Software Foundation, either version 3 of the License, or
   6  *  (at your option) any later version.
   7  *
   8  *  This program is distributed in the hope that it will be useful,
   9  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  *  GNU General Public License for more details.
  12  *
  13  *  You should have received a copy of the GNU General Public License
  14  *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
  15  */
  16 /* Library made by: g4lvanix
  17  * Github repository: https://github.com/g4lvanix/I2C-master-lib
  18  */
  19
  20 #include <avr/io.h>
  21 #include <util/twi.h>
  22
  23 #include "i2c_master.h"
  24 #include "timer.h"
  25 #include "wait.h"
  26
  27 #ifndef F_SCL
  28 #    define F_SCL 400000UL  // SCL frequency
  29 #endif
  30
  31 #define TWBR_val (((F_CPU / F_SCL) - 16) / 2)
  32
  33 void i2c_init(void) {
  34     TWSR = 0; /* no prescaler */
  35     TWBR = (uint8_t)TWBR_val;
  36
  37 #ifdef __AVR_ATmega32A__
  38     // set pull-up resistors on I2C bus pins
  39     PORTC |= 0b11;
  40
  41     // enable TWI (two-wire interface)
  42     TWCR |= (1 << TWEN);
  43
  44     // enable TWI interrupt and slave address ACK
  45     TWCR |= (1 << TWIE);
  46     TWCR |= (1 << TWEA);
  47 #endif
  48 }
  49
  50 i2c_status_t i2c_start(uint8_t address, uint16_t timeout) {
  51     // reset TWI control register
  52     TWCR = 0;
  53     // transmit START condition
  54     TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
  55
  56     uint16_t timeout_timer = timer_read();
  57     while (!(TWCR & (1 << TWINT))) {
  58         if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
  59             return I2C_STATUS_TIMEOUT;
  60         }
  61     }
  62
  63     // check if the start condition was successfully transmitted
  64     if (((TW_STATUS & 0xF8) != TW_START) && ((TW_STATUS & 0xF8) != TW_REP_START)) {
  65         return I2C_STATUS_ERROR;
  66     }
  67
  68     // load slave address into data register
  69     TWDR = address;
  70     // start transmission of address
  71     TWCR = (1 << TWINT) | (1 << TWEN);
  72
  73     timeout_timer = timer_read();
  74     while (!(TWCR & (1 << TWINT))) {
  75         if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
  76             return I2C_STATUS_TIMEOUT;
  77         }
  78     }
  79
  80     // check if the device has acknowledged the READ / WRITE mode
  81     uint8_t twst = TW_STATUS & 0xF8;
  82     if ((twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK)) {
  83         return I2C_STATUS_ERROR;
  84     }
  85
  86     return I2C_STATUS_SUCCESS;
  87 }
  88
  89 i2c_status_t i2c_write(uint8_t data, uint16_t timeout) {
  90     // load data into data register
  91     TWDR = data;
  92     // start transmission of data
  93     TWCR = (1 << TWINT) | (1 << TWEN);
  94
  95     uint16_t timeout_timer = timer_read();
  96     while (!(TWCR & (1 << TWINT))) {
  97         if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
  98             return I2C_STATUS_TIMEOUT;
  99         }
 100     }
 101
 102     if ((TW_STATUS & 0xF8) != TW_MT_DATA_ACK) {
 103         return I2C_STATUS_ERROR;
 104     }
 105
 106     return I2C_STATUS_SUCCESS;
 107 }
 108
 109 int16_t i2c_read_ack(uint16_t timeout) {
 110     // start TWI module and acknowledge data after reception
 111     TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
 112
 113     uint16_t timeout_timer = timer_read();
 114     while (!(TWCR & (1 << TWINT))) {
 115         if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
 116             return I2C_STATUS_TIMEOUT;
 117         }
 118     }
 119
 120     // return received data from TWDR
 121     return TWDR;
 122 }
 123
 124 int16_t i2c_read_nack(uint16_t timeout) {
 125     // start receiving without acknowledging reception
 126     TWCR = (1 << TWINT) | (1 << TWEN);
 127
 128     uint16_t timeout_timer = timer_read();
 129     while (!(TWCR & (1 << TWINT))) {
 130         if ((timeout != I2C_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) {
 131             return I2C_STATUS_TIMEOUT;
 132         }
 133     }
 134
 135     // return received data from TWDR
 136     return TWDR;
 137 }
 138
 139 i2c_status_t i2c_transmit(uint8_t address, const uint8_t* data, uint16_t length, uint16_t timeout) {
 140     i2c_status_t status = i2c_start(address | I2C_WRITE, timeout);
 141
 142     for (uint16_t i = 0; i < length && status >= 0; i++) {
 143         status = i2c_write(data[i], timeout);
 144     }
 145
 146     i2c_stop();
 147
 148     return status;
 149 }
 150
 151 i2c_status_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout) {
 152     i2c_status_t status = i2c_start(address | I2C_READ, timeout);
 153
 154     for (uint16_t i = 0; i < (length - 1) && status >= 0; i++) {
 155         status = i2c_read_ack(timeout);
 156         if (status >= 0) {
 157             data[i] = status;
 158         }
 159     }
 160
 161     if (status >= 0) {
 162         status = i2c_read_nack(timeout);
 163         if (status >= 0) {
 164             data[(length - 1)] = status;
 165         }
 166     }
 167
 168     i2c_stop();
 169
 170     return (status < 0) ? status : I2C_STATUS_SUCCESS;
 171 }
 172
 173 i2c_status_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, const uint8_t* data, uint16_t length, uint16_t timeout) {
 174     i2c_status_t status = i2c_start(devaddr | 0x00, timeout);
 175     if (status >= 0) {
 176         status = i2c_write(regaddr, timeout);
 177
 178         for (uint16_t i = 0; i < length && status >= 0; i++) {
 179             status = i2c_write(data[i], timeout);
 180         }
 181     }
 182
 183     i2c_stop();
 184
 185     return status;
 186 }
 187
 188 i2c_status_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout) {
 189     i2c_status_t status = i2c_start(devaddr, timeout);
 190     if (status < 0) {
 191         goto error;
 192     }
 193
 194     status = i2c_write(regaddr, timeout);
 195     if (status < 0) {
 196         goto error;
 197     }
 198
 199     status = i2c_start(devaddr | 0x01, timeout);
 200
 201     for (uint16_t i = 0; i < (length - 1) && status >= 0; i++) {
 202         status = i2c_read_ack(timeout);
 203         if (status >= 0) {
 204             data[i] = status;
 205         }
 206     }
 207
 208     if (status >= 0) {
 209         status = i2c_read_nack(timeout);
 210         if (status >= 0) {
 211             data[(length - 1)] = status;
 212         }
 213     }
 214
 215 error:
 216     i2c_stop();
 217
 218     return (status < 0) ? status : I2C_STATUS_SUCCESS;
 219 }
 220
 221 void i2c_stop(void) {
 222     // transmit STOP condition
 223     TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);
 224 }