1 | #define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)
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2 |
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3 | struct __FILE { int handle; };
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4 | FILE __stdout;
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5 | FILE __stdin;
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6 |
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7 | void usart1_init (unsigned long baudrate) {
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8 | NVIC->ISER[1] |= 0x00000020; //enable USART1 Interrupt (Nested Vector Interrupt Controller)
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9 |
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10 | RCC->APB2ENR |= RCC_APB2ENR_IOPAEN; //enable GPIOA clock
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11 |
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12 | GPIOA->CRH &= ~(0x00F0); //clear PA.9 configuration-bit
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13 | GPIOA->CRH |= (0x0BUL << 4); //Tx (PA9) - alt. out push-pull
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14 |
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15 | GPIOA->CRH &= ~(0x0F00); //clear PA.10 configuration-bit
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16 | GPIOA->CRH |= (0x04UL << 8); //Rx (PA10) - floating
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17 | RCC->APB2ENR |= RCC_APB2ENR_USART1EN; //enable USART1 clock
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18 |
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19 | USART1->BRR = 8000000L/baudrate; //set baudrate
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20 |
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21 | USART1->CR1 |= (USART_CR1_RE | USART_CR1_TE); //set RX, TX
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22 | USART1->CR1 |= USART_CR1_RXNEIE; //enable USART IRQ
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23 | USART1->CR1 |= USART_CR1_UE; //enable USART
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24 | }
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25 |
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26 | void usart2_init (unsigned long baudrate) {
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27 | RCC->APB2ENR |= RCC_APB2ENR_IOPAEN; //enable GPIOA clock
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28 |
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29 | AFIO->MAPR &= ~(AFIO_MAPR_USART2_REMAP); //no remap of RX & TX
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30 |
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31 | GPIOA->CRL &= ~(0x0F00); //clear PA.2 configuration-bits
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32 | GPIOA->CRL |= (0x0BUL << 8); //Tx (PA.2) - alt. out push-pull
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33 |
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34 | GPIOA->CRL &= ~(0xF000); //clear PA.3 configuration-bits
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35 | GPIOA->CRL |= (0x04UL << 12); //Rx (PA.3) - floating
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36 | RCC->APB1ENR |= RCC_APB1ENR_USART2EN; //enable USART2 clock
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37 |
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38 | USART2->BRR = 8000000L/baudrate; //set baudrate
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39 |
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40 | USART2->CR1 |= (USART_CR1_RE | USART_CR1_TE); //enable RX, TX
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41 | USART2->CR1 |= USART_CR1_UE; //enable USART
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42 | }
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43 |
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44 | void usart3_init (unsigned long baudrate) {
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45 | NVIC->ISER[1] |= 0x00000080; //enable USART1 Interrupt (Nested Vector Interrupt Controller)
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46 | RCC->APB2ENR |= RCC_APB2ENR_IOPBEN; //enable GPIOB clock
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47 |
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48 | AFIO->MAPR &= ~(AFIO_MAPR_USART3_REMAP); //no remap of RX & TX
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49 |
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50 | GPIOB->CRH = GPIOB->CRH & ~(0x00000F00) | (0x00000B00); //PB10 = Tx
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51 | //GPIOA->CRL |= (0x0BUL << 8); //Tx (PA.2) - alt. out push-pull
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52 | GPIOB->CRH = GPIOB->CRH & ~(0x0000F000) | (0x00004000); //PB11 = Rx
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53 | //GPIOA->CRL &= ~(0xF000); //PB11 = Rx
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54 | //GPIOA->CRL |= (0x04UL << 12); //Rx (PA.3) - floating
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55 | RCC->APB1ENR |= RCC_APB1ENR_USART3EN; //enable USART3 clock
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56 |
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57 | USART3->BRR = 8000000L/baudrate; //set baudrate
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58 |
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59 | USART3->CR1 |= (USART_CR1_RE | USART_CR1_TE); //enable RX, TX
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60 | USART3->CR1 |= USART_CR1_RXNEIE; //enable USART IRQ
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61 | USART3->CR1 |= USART_CR1_UE; //enable USART
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62 | }
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63 |
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64 | int send_char (char ch) {
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65 | while (!(USART2->SR & USART_SR_TXE)); //data transmit register empty?
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66 | USART2->DR = (ch & 0xFF); //write bytewise
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67 | return (ch);
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68 | }
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69 |
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70 | /*let send_char point to printf*/
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71 | PUTCHAR_PROTOTYPE
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72 | {
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73 | send_char((char) ch);
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74 | return ch;
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75 | }
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76 |
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77 |
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78 |
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79 | /*Put the received characters in a ringbuffer*/
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80 | void USART1_IRQHandler (void){
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81 | if((USART1->SR & USART_SR_RXNE)){
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82 | fifo_write(&fifo[0], USART1->DR);
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83 | }
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84 | }
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85 |
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86 | /*Put the received characters in a ringbuffer*/
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87 | void USART3_IRQHandler (void){
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88 | if((USART3->SR & USART_SR_RXNE)){
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89 | fifo_write(&fifo[1], USART3->DR);
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90 | }
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91 | }
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92 |
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93 | int main(void)
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94 | {
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95 |
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96 | uint8_t data[2] = {0,0};
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97 | uint8_t ret[2] = {0,0};
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98 |
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99 | //initialize ringbuffer
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100 | fifo_init(&fifo[0]);
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101 | fifo_init(&fifo[1]);
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102 |
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103 |
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104 | usart1_init(9600); //USART1 used for sending data
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105 | usart2_init(9600); //USART2 used for receiving data
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106 | usart3_init(9600); //USART3 used for receiving data
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107 |
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108 | for(;;){
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109 | __disable_irq(); //translate to CPSID i
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110 | //try to read from ringbuffer and put read char in 'data'
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111 | ret[0] = fifo_read(&fifo[0], &data[0]);
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112 | ret[1] = fifo_read(&fifo[1], &data[1]);
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113 | __enable_irq(); //translate to CPSIE i
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114 |
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115 | if(ret[0] == SUCCESS){ //if there was new char in ringbuffer
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116 | printf("%d", manipulate_data(data[0])); //manipulate data and write it out
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117 | }
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118 | if(ret[1] == SUCCESS){ //new character in buffer?
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119 | printf("%d", manipulate_data(data[0])); //manipulate data and write it out
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120 | }
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121 |
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122 | }
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123 | }
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