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Diffstat (limited to 'keyboards/exclusive/e6v2/bmc/i2c.c')
| -rw-r--r-- | keyboards/exclusive/e6v2/bmc/i2c.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/keyboards/exclusive/e6v2/bmc/i2c.c b/keyboards/exclusive/e6v2/bmc/i2c.c new file mode 100644 index 000000000..801242e0d --- /dev/null +++ b/keyboards/exclusive/e6v2/bmc/i2c.c @@ -0,0 +1,106 @@ +/* +Copyright 2016 Luiz Ribeiro <luizribeiro@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/>. +*/ + +// Please do not modify this file + +#include <avr/io.h> +#include <util/twi.h> + +#include "i2c.h" + +void i2c_set_bitrate(uint16_t bitrate_khz) { + uint8_t bitrate_div = ((F_CPU / 1000l) / bitrate_khz); + if (bitrate_div >= 16) { + bitrate_div = (bitrate_div - 16) / 2; + } + TWBR = bitrate_div; +} + +void i2c_init(void) { + // set pull-up resistors on I2C bus pins + PORTC |= 0b11; + + i2c_set_bitrate(400); + + // enable TWI (two-wire interface) + TWCR |= (1 << TWEN); + + // enable TWI interrupt and slave address ACK + TWCR |= (1 << TWIE); + TWCR |= (1 << TWEA); +} + +uint8_t i2c_start(uint8_t address) { + // reset TWI control register + TWCR = 0; + + // begin transmission and wait for it to end + TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN); + while (!(TWCR & (1<<TWINT))); + + // check if the start condition was successfully transmitted + if ((TWSR & 0xF8) != TW_START) { + return 1; + } + + // transmit address and wait + TWDR = address; + TWCR = (1<<TWINT) | (1<<TWEN); + 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; +} + +void i2c_stop(void) { + TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO); +} + +uint8_t i2c_write(uint8_t data) { + TWDR = data; + + // transmit data and wait + TWCR = (1<<TWINT) | (1<<TWEN); + while (!(TWCR & (1<<TWINT))); + + if ((TWSR & 0xF8) != TW_MT_DATA_ACK) { + return 1; + } + + return 0; +} + +uint8_t i2c_send(uint8_t address, uint8_t *data, uint16_t length) { + if (i2c_start(address)) { + return 1; + } + + for (uint16_t i = 0; i < length; i++) { + if (i2c_write(data[i])) { + return 1; + } + } + + i2c_stop(); + + return 0; +}
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