[原创] 【ST NUCLEO-U575ZI-Q 测评】串口收发测试

qinyunti 2022-12-15 21:33 楼主

前言

串口作为最常用的通讯接口，我们先实现串口的收发，后面标准输入输出，但因调试等都依赖于传口。

串口模块

参见《58 Low-power universal asynchronous receiver transmitter (LPUART)》

引脚

使用PG7-PG8 LPUART1-TX LPUART1-RX，对应AF8

LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOG);

/* PG7 TX */

LL_GPIO_InitTypeDef GPIO_InitStruct;

//LL_GPIO_StructInit(&GPIO_InitStruct);

GPIO_InitStruct.Pin = LL_GPIO_PIN_7;

GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;

GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_VERY_HIGH;

GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;

GPIO_InitStruct.Pull = LL_GPIO_PULL_UP;

GPIO_InitStruct.Alternate = LL_GPIO_AF_8;

LL_GPIO_Init(GPIOG, &GPIO_InitStruct);

/* PG8 RX */

GPIO_InitStruct.Pin = LL_GPIO_PIN_8;

GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;

GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_VERY_HIGH;

GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;

GPIO_InitStruct.Pull = LL_GPIO_PULL_UP;

GPIO_InitStruct.Alternate = LL_GPIO_AF_8;

LL_GPIO_Init(GPIOG, &GPIO_InitStruct);

时钟

从时钟树可以看到LPUART1时钟可以来源于SYSCLK->AHB->APB3->PCLK3

也可以来源于MSIK，HSI16，LSE。我们选择PCLK3。

AHB和APB3分频之前在RCC配置时设置

RCC_ClkInitTypeDef pRCC_ClkInitStruct;

pRCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK;

pRCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;

pRCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;

pRCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;

pRCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;

pRCC_ClkInitStruct.APB3CLKDivider = RCC_HCLK_DIV2;

HAL_RCC_ClockConfig(&pRCC_ClkInitStruct, FLASH_LATENCY_4);

这里分别是分频1和2所以 LPUART的输入时钟是160MHz/2=80MHz

使能时钟

LL_APB3_GRP1_EnableClock(LL_APB3_GRP1_PERIPH_LPUART1);

串口配置

LL_LPUART_InitTypeDef LPUART_InitStruct;

LPUART_InitStruct.BaudRate = 115200;

LPUART_InitStruct.DataWidth = LL_LPUART_DATAWIDTH_8B;

LPUART_InitStruct.HardwareFlowControl = LL_LPUART_HWCONTROL_NONE;

LPUART_InitStruct.Parity = LL_LPUART_PARITY_NONE;

LPUART_InitStruct.PrescalerValue = LL_LPUART_PRESCALER_DIV1;

LPUART_InitStruct.StopBits = LL_LPUART_STOPBITS_1;

LPUART_InitStruct.TransferDirection = LL_LPUART_DIRECTION_TX_RX;

LL_LPUART_Init(LPUART1, &LPUART_InitStruct);

中断配置

使能接收非空中断，发送非空中断暂时不使能(否则使能后马上回进入中断，后续实现中断发送再讲)

LL_LPUART_EnableIT_RXNE_RXFNE(LPUART1);

//LL_LPUART_EnableIT_TXE_TXFNF(LPUART1);

__NVIC_EnableIRQ(LPUART1_IRQn);

__NVIC_SetPriority(LPUART1_IRQn, 3);

LPUART_ISR中中断标志

RXNE中断时读RDR清除标志

TXE中断时写TDR清除标志。

中断处理

收到数据后原样返回

void LPUART1_IRQHandler(void)

{

if(LL_LPUART_IsActiveFlag_RXNE_RXFNE(LPUART1) == SET)

{

LL_LPUART_TransmitData8(LPUART1,LL_LPUART_ReceiveData8(LPUART1));

}

if(LL_LPUART_IsActiveFlag_TXE_TXFNF(LPUART1))

{

}

串口使能

LL_LPUART_Enable(LPUART1);

测试

添加uart.c

#include "stm32u575xx.h"

#include "stm32u5xx_ll_gpio.h"

#include "stm32u5xx_ll_bus.h"

#include "stm32u5xx_ll_lpuart.h"

void LPUART1_IRQHandler(void)

{

if(LL_LPUART_IsActiveFlag_RXNE_RXFNE(LPUART1) == SET)

{

LL_LPUART_TransmitData8(LPUART1,LL_LPUART_ReceiveData8(LPUART1));

}

if(LL_LPUART_IsActiveFlag_TXE_TXFNF(LPUART1))

{

}

void uart_init(void)

{

LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOG);

/* PG7 TX */

LL_GPIO_InitTypeDef GPIO_InitStruct;

//LL_GPIO_StructInit(&GPIO_InitStruct);

GPIO_InitStruct.Pin = LL_GPIO_PIN_7;

GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;

GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_VERY_HIGH;

GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;

GPIO_InitStruct.Pull = LL_GPIO_PULL_UP;

GPIO_InitStruct.Alternate = LL_GPIO_AF_8;

LL_GPIO_Init(GPIOG, &GPIO_InitStruct);

/* PG8 RX */

GPIO_InitStruct.Pin = LL_GPIO_PIN_8;

GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;

GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_VERY_HIGH;

GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;

GPIO_InitStruct.Pull = LL_GPIO_PULL_UP;

GPIO_InitStruct.Alternate = LL_GPIO_AF_8;

LL_GPIO_Init(GPIOG, &GPIO_InitStruct);

LL_APB3_GRP1_EnableClock(LL_APB3_GRP1_PERIPH_LPUART1);

LL_LPUART_InitTypeDef LPUART_InitStruct;

LPUART_InitStruct.BaudRate = 115200;

LPUART_InitStruct.DataWidth = LL_LPUART_DATAWIDTH_8B;

LPUART_InitStruct.HardwareFlowControl = LL_LPUART_HWCONTROL_NONE;

LPUART_InitStruct.Parity = LL_LPUART_PARITY_NONE;

LPUART_InitStruct.PrescalerValue = LL_LPUART_PRESCALER_DIV1;

LPUART_InitStruct.StopBits = LL_LPUART_STOPBITS_1;

LPUART_InitStruct.TransferDirection = LL_LPUART_DIRECTION_TX_RX;

LL_LPUART_Init(LPUART1, &LPUART_InitStruct);

LL_LPUART_EnableIT_RXNE_RXFNE(LPUART1);

//LL_LPUART_EnableIT_TXE_TXFNF(LPUART1);

__NVIC_EnableIRQ(LPUART1_IRQn);

__NVIC_SetPriority(LPUART1_IRQn, 3);

LL_LPUART_Enable(LPUART1);

}

uart.h

#ifndef UART_H

#define UART_H

void uart_init(void);

#endif

main.c

main中调用uart_init即可

#include "stm32u575xx.h"
#include "stm32u5xx_ll_gpio.h"
#include "stm32u5xx_ll_bus.h"
#include "uart.h"

void SysTick_Handler(void)
{
   static volatile uint32_t num = 0;
   if(num++ >= 1000)
   {
       LL_GPIO_TogglePin(GPIOB, 1u<<7);
       LL_GPIO_TogglePin(GPIOG, 1u<<2);
       LL_GPIO_TogglePin(GPIOC, 1u<<7);
       num=0;
   }
   HAL_IncTick();
}

void delay(uint32_t t)
{
volatile uint32_t timeout = t;
while(t--);
}

int main(void)
{
   HAL_Init();
   LL_AHB3_GRP1_EnableClock(LL_AHB3_GRP1_PERIPH_PWR);
   HAL_PWREx_EnableVddIO2();
   HAL_PWREx_ConfigSupply(PWR_SMPS_SUPPLY);
#if 1
   LL_AHB3_GRP1_EnableClock(LL_AHB3_GRP1_PERIPH_PWR);
   HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1);

   RCC_OscInitTypeDef pRCC_OscInitStruct;
   pRCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
   pRCC_OscInitStruct.HSIState = RCC_HSI_ON;
   pRCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
   pRCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
   pRCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
   pRCC_OscInitStruct.PLL.PLLM = 1;
   pRCC_OscInitStruct.PLL.PLLMBOOST = RCC_PLLMBOOST_DIV1;
   pRCC_OscInitStruct.PLL.PLLN = 20;
   pRCC_OscInitStruct.PLL.PLLP = 1;
   pRCC_OscInitStruct.PLL.PLLQ = 1;
   pRCC_OscInitStruct.PLL.PLLR = 2;
   pRCC_OscInitStruct.PLL.PLLRGE = RCC_PLLVCIRANGE_0;
   pRCC_OscInitStruct.PLL.PLLFRACN = 0; /* */
   HAL_RCC_OscConfig(&pRCC_OscInitStruct);

   RCC_ClkInitTypeDef pRCC_ClkInitStruct;
   pRCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK;
   pRCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
   pRCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
   pRCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
   pRCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
   pRCC_ClkInitStruct.APB3CLKDivider = RCC_HCLK_DIV2;
   HAL_RCC_ClockConfig(&pRCC_ClkInitStruct, FLASH_LATENCY_4);
#endif

   LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOB);
   LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOG);
   LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOC);

   LL_GPIO_InitTypeDef GPIO_InitStruct;
   //LL_GPIO_StructInit(&GPIO_InitStruct);
   GPIO_InitStruct.Pin = LL_GPIO_PIN_7;
   GPIO_InitStruct.Mode = LL_GPIO_MODE_OUTPUT;
   GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_VERY_HIGH;
   GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;
   GPIO_InitStruct.Pull = LL_GPIO_PULL_UP;
   GPIO_InitStruct.Alternate = LL_GPIO_AF_0;
   LL_GPIO_Init(GPIOB, &GPIO_InitStruct);

   GPIO_InitStruct.Pin = LL_GPIO_PIN_2;
   GPIO_InitStruct.Mode = LL_GPIO_MODE_OUTPUT;
   GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_HIGH;
   GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;
   GPIO_InitStruct.Pull = LL_GPIO_PULL_UP;
   GPIO_InitStruct.Alternate = LL_GPIO_AF_0;
   LL_GPIO_Init(GPIOG, &GPIO_InitStruct);

   GPIO_InitStruct.Pin = LL_GPIO_PIN_7;
   GPIO_InitStruct.Mode = LL_GPIO_MODE_OUTPUT;
   GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_VERY_HIGH;
   GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;
   GPIO_InitStruct.Pull = LL_GPIO_PULL_UP;
   GPIO_InitStruct.Alternate = LL_GPIO_AF_0;
   LL_GPIO_Init(GPIOC, &GPIO_InitStruct);

   uart_init();
   while(1)
   {

   }
}