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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 1 | ingob | 1 | /*############################################################################ |
| 2 | ############################################################################*/ |
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| 3 | |||
| 886 | killagreg | 4 | #include <avr/io.h> |
| 5 | #include <avr/interrupt.h> |
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| 6 | |||
| 1 | ingob | 7 | #include "main.h" |
| 886 | killagreg | 8 | #include "twimaster.h" |
| 9 | #include "fc.h" |
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| 1 | ingob | 10 | |
| 886 | killagreg | 11 | volatile uint8_t twi_state = 0; |
| 12 | volatile uint8_t motor = 0; |
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| 13 | volatile uint8_t motor_rx[8]; |
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| 1 | ingob | 14 | |
| 886 | killagreg | 15 | /**************************************************/ |
| 16 | /* Initialize I2C (TWI) */ |
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| 17 | /**************************************************/ |
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| 18 | void I2C_Init(void) |
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| 1 | ingob | 19 | { |
| 886 | killagreg | 20 | uint8_t sreg = SREG; |
| 21 | cli(); |
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| 22 | |||
| 23 | // SDA is INPUT |
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| 24 | DDRC &= ~(1<<DDC1); |
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| 25 | // SCL is output |
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| 26 | DDRC |= (1<<DDC0); |
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| 27 | // pull up SDA |
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| 28 | PORTC |= (1<<PORTC0)|(1<<PORTC1); |
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| 29 | |||
| 30 | // TWI Status Register |
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| 31 | // prescaler 1 (TWPS1 = 0, TWPS0 = 0) |
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| 32 | TWSR &= ~((1<<TWPS1)|(1<<TWPS0)); |
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| 33 | |||
| 34 | // set TWI Bit Rate Register |
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| 35 | TWBR = ((SYSCLK/SCL_CLOCK)-16)/2; |
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| 36 | |||
| 37 | SREG = sreg; |
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| 1 | ingob | 38 | } |
| 39 | |||
| 886 | killagreg | 40 | /****************************************/ |
| 41 | /* Start I2C */ |
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| 42 | /****************************************/ |
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| 43 | void I2C_Start(void) |
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| 1 | ingob | 44 | { |
| 886 | killagreg | 45 | // TWI Control Register |
| 46 | // clear TWI interrupt flag (TWINT=1) |
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| 47 | // disable TWI Acknowledge Bit (TWEA = 0) |
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| 48 | // enable TWI START Condition Bit (TWSTA = 1), MASTER |
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| 49 | // disable TWI STOP Condition Bit (TWSTO = 0) |
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| 50 | // disable TWI Write Collision Flag (TWWC = 0) |
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| 51 | // enable i2c (TWIE = 1) |
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| 52 | // enable TWI Interrupt (TWIE = 1) |
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| 53 | TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN) | (1<<TWIE); |
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| 1 | ingob | 54 | } |
| 55 | |||
| 886 | killagreg | 56 | /****************************************/ |
| 57 | /* Stop I2C */ |
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| 58 | /****************************************/ |
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| 59 | void I2C_Stop(void) |
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| 1 | ingob | 60 | { |
| 886 | killagreg | 61 | // TWI Control Register |
| 62 | // clear TWI interrupt flag (TWINT=1) |
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| 63 | // disable TWI Acknowledge Bit (TWEA = 0) |
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| 64 | // diable TWI START Condition Bit (TWSTA = 1), no MASTER |
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| 65 | // enable TWI STOP Condition Bit (TWSTO = 1) |
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| 66 | // disable TWI Write Collision Flag (TWWC = 0) |
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| 67 | // enable i2c (TWIE = 1) |
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| 68 | // disable TWI Interrupt (TWIE = 0) |
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| 69 | TWCR = (1<<TWINT) | (1<<TWSTO) | (1<<TWEN); |
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| 1 | ingob | 70 | } |
| 71 | |||
| 886 | killagreg | 72 | /****************************************/ |
| 73 | /* Reset I2C */ |
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| 74 | /****************************************/ |
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| 75 | void I2C_Reset(void) |
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| 173 | holgerb | 76 | { |
| 886 | killagreg | 77 | // stop i2c bus |
| 78 | I2C_Stop(); |
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| 79 | twi_state = 0; |
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| 80 | motor = TWDR; // ?? |
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| 81 | motor = 0; |
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| 82 | TWCR = (1<<TWINT); // reset to original state incl. interrupt flag reset |
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| 83 | TWAMR = 0; |
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| 84 | TWAR = 0; |
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| 85 | TWDR = 0; |
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| 86 | TWSR = 0; |
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| 87 | TWBR = 0; |
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| 88 | I2C_Init(); |
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| 89 | I2C_Start(); |
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| 90 | I2C_WriteByte(0); |
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| 173 | holgerb | 91 | } |
| 92 | |||
| 886 | killagreg | 93 | /****************************************/ |
| 94 | /* Write to I2C */ |
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| 95 | /****************************************/ |
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| 96 | void I2C_WriteByte(int8_t byte) |
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| 97 | { |
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| 98 | // move byte to send into TWI Data Register |
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| 1 | ingob | 99 | TWDR = byte; |
| 886 | killagreg | 100 | // clear interrupt flag (TWINT = 1) |
| 101 | // enable i2c bus (TWEN = 1) |
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| 102 | // enable intterupt (TWIW = 1) |
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| 1 | ingob | 103 | TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWIE); |
| 104 | } |
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| 105 | |||
| 886 | killagreg | 106 | |
| 107 | /****************************************/ |
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| 108 | /* Receive byte and send ACK */ |
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| 109 | /****************************************/ |
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| 110 | void I2C_ReceiveByte(void) |
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| 1 | ingob | 111 | { |
| 886 | killagreg | 112 | TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWIE) | (1<<TWEA); |
| 113 | } |
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| 114 | |||
| 115 | /****************************************/ |
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| 116 | /* I2C receive last byte and send no ACK*/ |
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| 117 | /****************************************/ |
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| 118 | void I2C_ReceiveLastByte(void) |
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| 119 | { |
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| 120 | TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWIE); |
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| 121 | } |
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| 122 | |||
| 123 | |||
| 124 | /****************************************/ |
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| 125 | /* I2C ISR */ |
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| 126 | /****************************************/ |
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| 127 | ISR (TWI_vect) |
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| 128 | |||
| 129 | { |
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| 130 | static uint8_t motorread = 0; |
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| 131 | |||
| 132 | switch (twi_state++) // First i2s_start from SendMotorData() |
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| 1 | ingob | 133 | { |
| 886 | killagreg | 134 | // Master Transmit |
| 135 | case 0: // Send SLA-W |
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| 136 | I2C_WriteByte(0x52+(motor*2)); |
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| 1 | ingob | 137 | break; |
| 886 | killagreg | 138 | case 1: // Send Data to Salve |
| 1 | ingob | 139 | switch(motor++) |
| 140 | { |
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| 141 | case 0: |
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| 886 | killagreg | 142 | I2C_WriteByte(Motor_Front); |
| 1 | ingob | 143 | break; |
| 886 | killagreg | 144 | case 1: |
| 145 | I2C_WriteByte(Motor_Rear); |
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| 1 | ingob | 146 | break; |
| 147 | case 2: |
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| 886 | killagreg | 148 | I2C_WriteByte(Motor_Right); |
| 1 | ingob | 149 | break; |
| 150 | case 3: |
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| 886 | killagreg | 151 | I2C_WriteByte(Motor_Left); |
| 1 | ingob | 152 | break; |
| 153 | } |
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| 154 | break; |
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| 886 | killagreg | 155 | case 2: // repeat case 0+1 for all Slaves |
| 1 | ingob | 156 | if (motor<4) twi_state = 0; |
| 886 | killagreg | 157 | I2C_Start(); // Repeated start -> switch salve or switch Master Transmit -> Master Receive |
| 1 | ingob | 158 | break; |
| 886 | killagreg | 159 | |
| 160 | // Master Receive |
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| 161 | case 3: // Send SLA-R |
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| 162 | I2C_WriteByte(0x53+(motorread*2)); |
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| 163 | break; |
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| 1 | ingob | 164 | case 4: |
| 886 | killagreg | 165 | //Transmit 1st byte |
| 166 | I2C_ReceiveByte(); |
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| 1 | ingob | 167 | break; |
| 886 | killagreg | 168 | case 5: //Read 1st byte and transmit 2nd Byte |
| 1 | ingob | 169 | motor_rx[motorread] = TWDR; |
| 886 | killagreg | 170 | I2C_ReceiveLastByte(); |
| 171 | break; |
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| 172 | case 6: |
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| 173 | //Read 2nd byte |
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| 174 | motor_rx[motorread+4] = TWDR; |
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| 175 | motorread++; |
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| 176 | if (motorread > 3) motorread=0; |
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| 173 | holgerb | 177 | |
| 886 | killagreg | 178 | default: |
| 179 | I2C_Stop(); |
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| 180 | twi_state = 0; |
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| 173 | holgerb | 181 | I2CTimeout = 10; |
| 886 | killagreg | 182 | motor = 0; |
| 1 | ingob | 183 | } |
| 184 | } |