我不太清楚为什么Hardwar NSS为什么不能在发送完以后自动拉高，我尝试过通过在HAL_SPI_Transmit_DMA函数前后添加开关nss或者开关spi的指令，但是这种做法会使得spi无法启动，如果不添加将会让cs信号持续低电平，下面是我的控制代码和spi配置代码。

/ USER CODE BEGIN Header /

/**

---

• @file dma.c

• @brief This file provides code for the configuration

• of all the requested memory to memory DMA transfers.

• @attention

• Copyright (c) 2026 STMicroelectronics.

• All rights reserved.

• This software is licensed under terms that can be found in the LICENSE file

• in the root directory of this software component.

• If no LICENSE file comes with this software, it is provided AS-IS.

---

*/

/ USER CODE END Header /

/ Includes ------------------------------------------------------------------/

include "dma.h"

/ USER CODE BEGIN 0 /

/ USER CODE END 0 /

/----------------------------------------------------------------------------/

/ Configure DMA /

/----------------------------------------------------------------------------/

/ USER CODE BEGIN 1 /

/ USER CODE END 1 /

/**

• Enable DMA controller clock

*/

void MX_DMA_Init(void)

{

/ DMA controller clock enable /

__HAL_RCC_DMA1_CLK_ENABLE();

/ DMA interrupt init /

/ DMA1_Channel3_IRQn interrupt configuration /

HAL_NVIC_SetPriority(DMA1_Channel3_IRQn, 0, 0);

HAL_NVIC_EnableIRQ(DMA1_Channel3_IRQn);

}

/ USER CODE BEGIN 2 /

static uint8_t dac_tx_buf[3];

uint8_t wTransferState = TRANSFER_COMPLETE;

uint8_t i=0;

uint16_t val;

void DAC_WriteA_DMA(uint16_t data)

{

while(wTransferState == TRANSFER_WAIT);

dac_tx_buf[0] = DAC_CH_A;

dac_tx_buf[1] = (data >> 8) & 0xFF;

dac_tx_buf[2] = data & 0xFF;

wTransferState = TRANSFER_WAIT;

HAL_SPI_Transmit_DMA(&hspi1, dac_tx_buf, 3); }

void HAL_SPI_TxCpltCallback(SPI_HandleTypeDef *hspi)

{

if(hspi == &hspi1)

{

wTransferState = TRANSFER_COMPLETE;

} }

void DAC_GenSawtooth_2P2KHz(void)

{

static uint16_t dac_val = 0;

DAC_WriteA_DMA(dac_val);

dac_val += 384;

if(dac_val >= MAX_DAC_VALUE)

{

dac_val = 0;

} }

/ USER CODE END 2 /

/ USER CODE BEGIN Header /

/**

---

• @file spi.c

• @brief This file provides code for the configuration

• of the SPI instances.

• @attention

• Copyright (c) 2026 STMicroelectronics.

• All rights reserved.

• This software is licensed under terms that can be found in the LICENSE file

• in the root directory of this software component.

• If no LICENSE file comes with this software, it is provided AS-IS.

---

*/

/ USER CODE END Header /

/ Includes ------------------------------------------------------------------/

include "spi.h"

/ USER CODE BEGIN 0 /

/ USER CODE END 0 /

SPI_HandleTypeDef hspi1;

DMA_HandleTypeDef hdma_spi1_tx;

/ SPI1 init function /

void MX_SPI1_Init(void)

{

/ USER CODE BEGIN SPI1_Init 0 /

/ USER CODE END SPI1_Init 0 /

/ USER CODE BEGIN SPI1_Init 1 /

/ USER CODE END SPI1_Init 1 /

hspi1.Instance = SPI1;

hspi1.Init.Mode = SPI_MODE_MASTER;

hspi1.Init.Direction = SPI_DIRECTION_2LINES;

hspi1.Init.DataSize = SPI_DATASIZE_8BIT;

hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;

hspi1.Init.CLKPhase = SPI_PHASE_2EDGE;

hspi1.Init.NSS = SPI_NSS_HARD_OUTPUT;

hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_16;

hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;

hspi1.Init.TIMode = SPI_TIMODE_DISABLE;

hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;

hspi1.Init.CRCPolynomial = 10;

if (HAL_SPI_Init(&hspi1) != HAL_OK)

{

Error_Handler(); }

/ USER CODE BEGIN SPI1_Init 2 /

/ USER CODE END SPI1_Init 2 /

}

void HAL_SPI_MspInit(SPI_HandleTypeDef* spiHandle)

{

GPIO_InitTypeDef GPIO_InitStruct = {0};

if(spiHandle->Instance==SPI1)

{

/ USER CODE BEGIN SPI1_MspInit 0 /

/ USER CODE END SPI1_MspInit 0 /

/ SPI1 clock enable /

__HAL_RCC_SPI1_CLK_ENABLE();

__HAL_RCC_GPIOA_CLK_ENABLE();

/**SPI1 GPIO Configuration

PA4 ------> SPI1_NSS

PA5 ------> SPI1_SCK

PA7 ------> SPI1_MOSI

*/

GPIO_InitStruct.Pin = GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_7;

GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;

GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;

HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

/ SPI1 DMA Init /

/ SPI1_TX Init /

hdma_spi1_tx.Instance = DMA1_Channel3;

hdma_spi1_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;

hdma_spi1_tx.Init.PeriphInc = DMA_PINC_DISABLE;

hdma_spi1_tx.Init.MemInc = DMA_MINC_ENABLE;

hdma_spi1_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;

hdma_spi1_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;

hdma_spi1_tx.Init.Mode = DMA_NORMAL;

hdma_spi1_tx.Init.Priority = DMA_PRIORITY_VERY_HIGH;

if (HAL_DMA_Init(&hdma_spi1_tx) != HAL_OK)

{

Error_Handler();

}

__HAL_LINKDMA(spiHandle,hdmatx,hdma_spi1_tx);

/ SPI1 interrupt Init /

HAL_NVIC_SetPriority(SPI1_IRQn, 0, 0);

HAL_NVIC_EnableIRQ(SPI1_IRQn); / USER CODE BEGIN SPI1_MspInit 1 /

/ USER CODE END SPI1_MspInit 1 /

}

}

void HAL_SPI_MspDeInit(SPI_HandleTypeDef* spiHandle)

{

if(spiHandle->Instance==SPI1)

{

/ USER CODE BEGIN SPI1_MspDeInit 0 /

/ USER CODE END SPI1_MspDeInit 0 /

/ Peripheral clock disable /

__HAL_RCC_SPI1_CLK_DISABLE();

/**SPI1 GPIO Configuration

PA4 ------> SPI1_NSS

PA5 ------> SPI1_SCK

PA7 ------> SPI1_MOSI

*/

HAL_GPIO_DeInit(GPIOA, GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_7);

/ SPI1 DMA DeInit /

HAL_DMA_DeInit(spiHandle->hdmatx);

/ SPI1 interrupt Deinit /

HAL_NVIC_DisableIRQ(SPI1_IRQn); / USER CODE BEGIN SPI1_MspDeInit 1 /

/ USER CODE END SPI1_MspDeInit 1 /

}

}

/ USER CODE BEGIN 1 /

/ USER CODE END 1 /

试了一下，禁止SPI工作，似乎也没有拉高。
不过这个手册上也说了，不会自动拉高的。
从应用上讲，控制从设备想拉高的话，开始通过IO口比较灵活，在开始时拉低，在完成的回调里拉高。

估计stm32早期的32F系列这个地方都有这个缺陷，后来新推出的STM32G/H/U等系列的SPI都支持NSSP模式，即发完一串数据后可以自动拉高，不要再手动去拉高。

我们做选型时尽量选择新推出的系列，其实性价比更高。