diff options
Diffstat (limited to 'quantum/split_common/i2c.c')
| -rw-r--r-- | quantum/split_common/i2c.c | 184 |
1 files changed, 0 insertions, 184 deletions
diff --git a/quantum/split_common/i2c.c b/quantum/split_common/i2c.c deleted file mode 100644 index 45e958b39..000000000 --- a/quantum/split_common/i2c.c +++ /dev/null | |||
| @@ -1,184 +0,0 @@ | |||
| 1 | #include <util/twi.h> | ||
| 2 | #include <avr/io.h> | ||
| 3 | #include <stdlib.h> | ||
| 4 | #include <avr/interrupt.h> | ||
| 5 | #include <util/twi.h> | ||
| 6 | #include <stdbool.h> | ||
| 7 | #include "i2c.h" | ||
| 8 | #include "split_flags.h" | ||
| 9 | |||
| 10 | // Limits the amount of we wait for any one i2c transaction. | ||
| 11 | // Since were running SCL line 100kHz (=> 10μs/bit), and each transactions is | ||
| 12 | // 9 bits, a single transaction will take around 90μs to complete. | ||
| 13 | // | ||
| 14 | // (F_CPU/SCL_CLOCK) => # of μC cycles to transfer a bit | ||
| 15 | // poll loop takes at least 8 clock cycles to execute | ||
| 16 | #define I2C_LOOP_TIMEOUT (9+1)*(F_CPU/SCL_CLOCK)/8 | ||
| 17 | |||
| 18 | #define BUFFER_POS_INC() (slave_buffer_pos = (slave_buffer_pos+1)%SLAVE_BUFFER_SIZE) | ||
| 19 | |||
| 20 | volatile uint8_t i2c_slave_buffer[SLAVE_BUFFER_SIZE]; | ||
| 21 | |||
| 22 | static volatile uint8_t slave_buffer_pos; | ||
| 23 | static volatile bool slave_has_register_set = false; | ||
| 24 | |||
| 25 | // Wait for an i2c operation to finish | ||
| 26 | inline static | ||
| 27 | void i2c_delay(void) { | ||
| 28 | uint16_t lim = 0; | ||
| 29 | while(!(TWCR & (1<<TWINT)) && lim < I2C_LOOP_TIMEOUT) | ||
| 30 | lim++; | ||
| 31 | |||
| 32 | // easier way, but will wait slightly longer | ||
| 33 | // _delay_us(100); | ||
| 34 | } | ||
| 35 | |||
| 36 | // Setup twi to run at 100kHz | ||
| 37 | void i2c_master_init(void) { | ||
| 38 | // no prescaler | ||
| 39 | TWSR = 0; | ||
| 40 | // Set TWI clock frequency to SCL_CLOCK. Need TWBR>10. | ||
| 41 | // Check datasheets for more info. | ||
| 42 | TWBR = ((F_CPU/SCL_CLOCK)-16)/2; | ||
| 43 | } | ||
| 44 | |||
| 45 | // Start a transaction with the given i2c slave address. The direction of the | ||
| 46 | // transfer is set with I2C_READ and I2C_WRITE. | ||
| 47 | // returns: 0 => success | ||
| 48 | // 1 => error | ||
| 49 | uint8_t i2c_master_start(uint8_t address) { | ||
| 50 | TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTA); | ||
| 51 | |||
| 52 | i2c_delay(); | ||
| 53 | |||
| 54 | // check that we started successfully | ||
| 55 | if ( (TW_STATUS != TW_START) && (TW_STATUS != TW_REP_START)) | ||
| 56 | return 1; | ||
| 57 | |||
| 58 | TWDR = address; | ||
| 59 | TWCR = (1<<TWINT) | (1<<TWEN); | ||
| 60 | |||
| 61 | i2c_delay(); | ||
| 62 | |||
| 63 | if ( (TW_STATUS != TW_MT_SLA_ACK) && (TW_STATUS != TW_MR_SLA_ACK) ) | ||
| 64 | return 1; // slave did not acknowledge | ||
| 65 | else | ||
| 66 | return 0; // success | ||
| 67 | } | ||
| 68 | |||
| 69 | |||
| 70 | // Finish the i2c transaction. | ||
| 71 | void i2c_master_stop(void) { | ||
| 72 | TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO); | ||
| 73 | |||
| 74 | uint16_t lim = 0; | ||
| 75 | while(!(TWCR & (1<<TWSTO)) && lim < I2C_LOOP_TIMEOUT) | ||
| 76 | lim++; | ||
| 77 | } | ||
| 78 | |||
| 79 | // Write one byte to the i2c slave. | ||
| 80 | // returns 0 => slave ACK | ||
| 81 | // 1 => slave NACK | ||
| 82 | uint8_t i2c_master_write(uint8_t data) { | ||
| 83 | TWDR = data; | ||
| 84 | TWCR = (1<<TWINT) | (1<<TWEN); | ||
| 85 | |||
| 86 | i2c_delay(); | ||
| 87 | |||
| 88 | // check if the slave acknowledged us | ||
| 89 | return (TW_STATUS == TW_MT_DATA_ACK) ? 0 : 1; | ||
| 90 | } | ||
| 91 | |||
| 92 | uint8_t i2c_master_write_data(void *const TXdata, uint8_t dataLen) { | ||
| 93 | |||
| 94 | uint8_t *data = (uint8_t *)TXdata; | ||
| 95 | int err = 0; | ||
| 96 | |||
| 97 | for (int i = 0; i < dataLen; i++) { | ||
| 98 | err = i2c_master_write(data[i]); | ||
| 99 | |||
| 100 | if ( err ) | ||
| 101 | return err; | ||
| 102 | } | ||
| 103 | |||
| 104 | return err; | ||
| 105 | |||
| 106 | } | ||
| 107 | |||
| 108 | // Read one byte from the i2c slave. If ack=1 the slave is acknowledged, | ||
| 109 | // if ack=0 the acknowledge bit is not set. | ||
| 110 | // returns: byte read from i2c device | ||
| 111 | uint8_t i2c_master_read(int ack) { | ||
| 112 | TWCR = (1<<TWINT) | (1<<TWEN) | (ack<<TWEA); | ||
| 113 | |||
| 114 | i2c_delay(); | ||
| 115 | return TWDR; | ||
| 116 | } | ||
| 117 | |||
| 118 | void i2c_reset_state(void) { | ||
| 119 | TWCR = 0; | ||
| 120 | } | ||
| 121 | |||
| 122 | void i2c_slave_init(uint8_t address) { | ||
| 123 | TWAR = address << 0; // slave i2c address | ||
| 124 | // TWEN - twi enable | ||
| 125 | // TWEA - enable address acknowledgement | ||
| 126 | // TWINT - twi interrupt flag | ||
| 127 | // TWIE - enable the twi interrupt | ||
| 128 | TWCR = (1<<TWIE) | (1<<TWEA) | (1<<TWINT) | (1<<TWEN); | ||
| 129 | } | ||
| 130 | |||
| 131 | ISR(TWI_vect); | ||
| 132 | |||
| 133 | ISR(TWI_vect) { | ||
| 134 | uint8_t ack = 1; | ||
| 135 | switch(TW_STATUS) { | ||
| 136 | case TW_SR_SLA_ACK: | ||
| 137 | // this device has been addressed as a slave receiver | ||
| 138 | slave_has_register_set = false; | ||
| 139 | break; | ||
| 140 | |||
| 141 | case TW_SR_DATA_ACK: | ||
| 142 | // this device has received data as a slave receiver | ||
| 143 | // The first byte that we receive in this transaction sets the location | ||
| 144 | // of the read/write location of the slaves memory that it exposes over | ||
| 145 | // i2c. After that, bytes will be written at slave_buffer_pos, incrementing | ||
| 146 | // slave_buffer_pos after each write. | ||
| 147 | if(!slave_has_register_set) { | ||
| 148 | slave_buffer_pos = TWDR; | ||
| 149 | // don't acknowledge the master if this memory loctaion is out of bounds | ||
| 150 | if ( slave_buffer_pos >= SLAVE_BUFFER_SIZE ) { | ||
| 151 | ack = 0; | ||
| 152 | slave_buffer_pos = 0; | ||
| 153 | } | ||
| 154 | |||
| 155 | slave_has_register_set = true; | ||
| 156 | } else { | ||
| 157 | i2c_slave_buffer[slave_buffer_pos] = TWDR; | ||
| 158 | |||
| 159 | if ( slave_buffer_pos == I2C_BACKLIT_START) { | ||
| 160 | BACKLIT_DIRTY = true; | ||
| 161 | } else if ( slave_buffer_pos == (I2C_RGB_START+3)) { | ||
| 162 | RGB_DIRTY = true; | ||
| 163 | } | ||
| 164 | |||
| 165 | BUFFER_POS_INC(); | ||
| 166 | } | ||
| 167 | break; | ||
| 168 | |||
| 169 | case TW_ST_SLA_ACK: | ||
| 170 | case TW_ST_DATA_ACK: | ||
| 171 | // master has addressed this device as a slave transmitter and is | ||
| 172 | // requesting data. | ||
| 173 | TWDR = i2c_slave_buffer[slave_buffer_pos]; | ||
| 174 | BUFFER_POS_INC(); | ||
| 175 | break; | ||
| 176 | |||
| 177 | case TW_BUS_ERROR: // something went wrong, reset twi state | ||
| 178 | TWCR = 0; | ||
| 179 | default: | ||
| 180 | break; | ||
| 181 | } | ||
| 182 | // Reset everything, so we are ready for the next TWI interrupt | ||
| 183 | TWCR |= (1<<TWIE) | (1<<TWINT) | (ack<<TWEA) | (1<<TWEN); | ||
| 184 | } | ||
