1 | #include "i2c.h"
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2 |
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3 | void InitI2C()
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4 | {
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5 | I2C_InitTypeDef I2C_InitStructure;
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6 | GPIO_InitTypeDef GPIO_InitStructure;
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7 |
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8 | SystemInit();
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9 |
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10 | RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
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11 | RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);
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12 |
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13 | /* Reset I2Cx IP */
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14 | RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, ENABLE);
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15 |
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16 | /* Release reset signal of I2Cx IP */
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17 | RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, DISABLE);
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18 |
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19 | GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
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20 | GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
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21 | GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD; // Open Drain, I2C bus pulled high externally
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22 | GPIO_Init(GPIOB, &GPIO_InitStructure);
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23 |
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24 |
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25 | I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
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26 | //I2C_InitStructure.I2C_OwnAddress1 = 0x00; //Eigene Adresse für Slave oder Multimaster betrieb, ansonsten irrelevant
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27 | I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;
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28 | I2C_InitStructure.I2C_Ack = I2C_Ack_Disable;
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29 | I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit; //Adress-Modus, normalerweise 7-Bit
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30 | I2C_InitStructure.I2C_ClockSpeed = 50000; //Taktgeschwindigkeit von SCL, hier 50kHz
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31 |
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32 | I2C_Init(I2C1, &I2C_InitStructure);
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33 |
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34 | I2C_ITConfig(I2C1, I2C_IT_EVT | I2C_IT_BUF, DISABLE); //Keine Interrupts
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35 |
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36 | I2C_Cmd(I2C1, ENABLE);
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37 | }
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38 |
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39 | void I2C_start(I2C_TypeDef* I2Cx, uint8_t address, uint8_t direction){
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40 | // wait until I2C1 is not busy any more
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41 | while(I2C_GetFlagStatus(I2Cx, I2C_FLAG_BUSY));
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42 |
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43 | // Send I2C1 START condition
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44 | I2C_GenerateSTART(I2Cx, ENABLE);
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45 |
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46 | // wait for I2C1 EV5 --> Slave has acknowledged start condition
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47 | while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT));
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48 |
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49 | // Send slave Address for write
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50 | I2C_Send7bitAddress(I2Cx, address, direction);
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51 |
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52 | /* wait for I2Cx EV6, check if
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53 | * either Slave has acknowledged Master transmitter or
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54 | * Master receiver mode, depending on the transmission
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55 | * direction
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56 | */
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57 | if(direction == I2C_Direction_Transmitter){
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58 | GPIOC->BSRR = 1<<8; //Switch on blue
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59 | while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)); // Here it hangs...
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60 | GPIOC->BSRR = 1<<9 ; //Switch green on
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61 | }
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62 | else if(direction == I2C_Direction_Receiver){
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63 | while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));
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64 | }
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65 | }
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66 |
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67 | void I2C_restart(I2C_TypeDef * I2Cx, uint8_t address, uint8_t direction)
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68 | {
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69 | while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_TRANSMITTING));
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70 | I2Cx->CR1 |= I2C_CR1_START;
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71 |
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72 | while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
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73 | while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT));
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74 |
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75 | // Send slave Address for write
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76 | I2C_Send7bitAddress(I2Cx, address, direction);
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77 |
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78 | /* wait for I2Cx EV6, check if
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79 | * either Slave has acknowledged Master transmitter or
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80 | * Master receiver mode, depending on the transmission
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81 | * direction
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82 | */
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83 | if(direction == I2C_Direction_Transmitter){
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84 | while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
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85 | }
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86 | else if(direction == I2C_Direction_Receiver){
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87 | while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));
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88 | }
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89 | }
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90 |
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91 | void I2C_write(I2C_TypeDef* I2Cx, uint8_t data)
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92 | {
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93 | // wait for I2C1 EV8 --> last byte is still being transmitted (last byte in SR, buffer empty), next byte can already be written
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94 | while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_TRANSMITTING));
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95 | I2C_SendData(I2Cx, data);
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96 | }
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97 |
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98 |
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99 | uint8_t I2C_read_ack(I2C_TypeDef* I2Cx){
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100 | // enable acknowledge of received data
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101 | I2C_AcknowledgeConfig(I2Cx, ENABLE);
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102 | // wait until one byte has been received
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103 | while( !I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED) );
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104 | // read data from I2C data register and return data byte
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105 | uint8_t data = I2C_ReceiveData(I2Cx);
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106 | return data;
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107 | }
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108 |
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109 |
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110 | uint8_t I2C_read_nack(I2C_TypeDef* I2Cx){
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111 | // disable acknowledge of received data
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112 | // nack also generates stop condition after last byte received
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113 | // see reference manual for more info
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114 | I2C_AcknowledgeConfig(I2Cx, DISABLE);
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115 | I2C_GenerateSTOP(I2Cx, ENABLE);
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116 | // wait until one byte has been received
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117 | while( !I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED) );
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118 | // read data from I2C data register and return data byte
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119 | uint8_t data = I2C_ReceiveData(I2Cx);
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120 | return data;
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121 | }
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122 |
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123 |
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124 | void I2C_stop(I2C_TypeDef* I2Cx){
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125 | while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
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126 | // Send I2C1 STOP Condition after last byte has been transmitted
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127 | I2C_GenerateSTOP(I2Cx, ENABLE);
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128 | // wait for I2C1 EV8_2 --> byte has been transmitted
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129 | while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
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130 | }
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