91 lines
1.9 KiB
C
91 lines
1.9 KiB
C
#include "lidar.h"
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volatile uint8_t usart3_index = 0;
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volatile uint8_t usart3_checksum = 0;
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volatile uint8_t usart3_frame_ready = 0;
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static lidar_data_buf buffer;
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static uint8_t* buff_data = (uint8_t*)&buffer;
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void lidar_init()
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{
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RCC->AHB2ENR |= RCC_AHB2ENR_GPIOBEN;
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// port 11 alt func mode
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GPIOB->MODER &= ~(3 << (11 * 2));
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GPIOB->MODER |= 2 << (11 * 2);
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// set AF7 on AFRegister for GPIOB11
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GPIOB->AFR[1] &= ~(0xF << 12);
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GPIOB->AFR[1] |= 7 << 12;
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// very high speed
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GPIOB->OSPEEDR |= 3 << (11 * 2);
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// pull-up
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GPIOB->PUPDR &= ~(3 << (11 * 2));
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GPIOB->PUPDR |= 1 << (11 * 2);
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// SYSCLK selected as USART3 clock
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RCC->CCIPR &= ~(RCC_CCIPR_USART3SEL);
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RCC->CCIPR |= 1 << RCC_CCIPR_USART3SEL_Pos;
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RCC->APB1ENR1 |= RCC_APB1ENR1_USART3EN;
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USART3->CR1 = 0;
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USART3->CR2 = 0;
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USART3->CR3 = 0;
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USART3->BRR = 16000000UL / 115200UL;
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// parity control disable
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USART3->CR1 &= ~(USART_CR1_PCE);
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// word length 8 bit
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USART3->CR1 &= ~USART_CR1_M1 & ~USART_CR1_M0;
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// 1 stop bit
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USART3->CR2 &= ~USART_CR2_STOP;
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// receiver enable
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// interrupt generated whenever ORE = 1 or RXNE = 1
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USART3->CR1 |= USART_CR1_RE | USART_CR1_RXNEIE;
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// overrun disable
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USART3->CR3 |= USART_CR3_OVRDIS;
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// USART3 enable
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USART3->CR1 |= USART_CR1_UE;
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// Interrupt enable
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NVIC_EnableIRQ(USART3_IRQn);
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}
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void USART3_IRQHandler()
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{
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if (USART3->ISR & USART_ISR_RXNE)
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{
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uint8_t b = USART3->RDR;
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if (usart3_index < 2)
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{
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if (b == USART3_START_BYTE)
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buff_data[usart3_index++] = b;
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}
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else if (usart3_index < USART3_FRAME_SIZE)
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buff_data[usart3_index++] = b;
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if (usart3_index == USART3_FRAME_SIZE)
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{
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for (uint8_t i = 0; i < USART3_FRAME_SIZE; ++i) usart3_checksum += buff_data[i];
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if (buffer.checksum == usart3_checksum)
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{
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usart3_index = 0;
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usart3_frame_ready = 1;
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}
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else
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{
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usart3_index = 0;
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usart3_frame_ready = 0;
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}
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}
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}
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} |