SPI (串行外设接口)

简介

使用特定同步协议与外部器件进行半双工、全双工和单工同步串行通信。 一个 SPI 总线只支持一个 Master，但可以有一个或多个 Slave。 在 SPI 应用架构中，SPI Master 作为主机，负责输出时钟和片选信号给 Slave 器件。

ET6001提供 3 组 1 线 SPI Master 接口 和 1 组 1 线 SPI Slave 接口。

功能概述

  • 支持接收端采样延迟

  • 支持通过软件配置输出时钟的有效相位和极性

  • 数据帧长度可配置，最大支持16bit传输数据帧

  • 支持硬件DMA握手

  • 支持中断上报

  • 支持 TX-RX loopback 测试

  • SPI Master 最高写时钟和最高读时钟均为 25MHz

  • SPI Slave 最高写时钟和最高读时钟均为 12.5MHz

  • SPI Master0 接收和发送FIFO 深度为 32，SPI Master1、2 和 SPI Slave 接收和发送 FIFO 深度为 16，FIFO 宽度均为 16bit

软件配置流程

基础收发配置流程如下：

  1. 配置IOMUX 配置对应串口引脚为SPI模式

  2. 配置SPI Master 调用 SPI_setConfig() 传入SPIx和参数结构体指针

  3. 使能SPI 调用 SPI_enableModule() 传入SPIx使能相应SPI

  4. 数据收发 调用 SPI_writeDataBlockingFIFO() 或 SPI_readDataBlockingFIFO() 传入SPIx和数据/数据指针，数据指针指向要接收的数据

SPI Master 时钟速率配置说明

SPI 的输入时钟来自APB3总线时钟，可通过 CRG_getAPB3Clock() 获取， 默认配置为100MHz。

配置SPI Master 时钟速率的公式如下：

\[baudrate = \frac{f_{APB3}}{DIV}\]

注意

DIV 的取值范围为 2~65535，且必须为偶数。

配置SPI Master 时钟速率的方法有两种：

  1. 通过 SPI_setConfig() 配置 SPI Master 时钟速率，传入参数结构体指针中的 baudrate 字段即可。

  2. 通过 SPI_setBaudRate() 配置 SPI Master 时钟速率。

应用示例

API Reference

Header File

Functions

void SPI_enableModule(SPI_Type *SPIx)

enable module

参数:

SPIx –

void SPI_disableModule(SPI_Type *SPIx)

disable module

参数:

SPIx –

void SPI_setcharLength(SPI_Type *SPIx, uint16_t charLength)

set data length

参数:

  • SPIx –

  • charLength –

void SPI_setCSLow(SPI_Type *SPIx)

set the selected chip signal to retain LOW

参数:

SPIx –

void SPI_setCSHigh(SPI_Type *SPIx)

set the selected chip signal to retain HIGH

参数:

SPIx –

void SPI_selectChip(SPI_Type *SPIx, uint8_t slaveIndex)

choose or change the slave for master to transmit data

参数:

  • SPIx –

  • slaveIndex – parameters are in the “ext6x_spi.h” SPI_CS_NONE SPI_CS0 SPI_CS1 SPI_CS2 SPI_CS3

void SPI_configFrameNum(SPI_Type *SPIx, uint16_t num)

Configure frame number to Receive when Transmit mode is SPI_RECEIVE or SPI_EEPROM_READ.

参数:

  • SPIx –

  • num –

void SPI_configTransMode(SPI_Type *SPIx, SPI_TransferMode mode)

Configure Transfer mode.

参数:

  • SPIx –

  • mode –

void SPI_resetFIFO(SPI_Type *SPIx)

reset fifo

参数:

SPIx –

void SPI_setFIFOInterruptLevel(SPI_Type *SPIx, uint8_t txLevel, uint8_t rxLevel)

Set FIFO interrupt thresholds for transmit and receive.

备注

Threshold values are checked by IS_SPI_FIFO_THRESHOLD macro to ensure they are less than SPI_MAX_FIFO_DEPTH

参数:

  • SPIx – Pointer to SPI peripheral

  • txLevel – Transmit FIFO interrupt threshold (valid range: 0 to SPI_MAX_FIFO_DEPTH)

  • rxLevel – Receive FIFO interrupt threshold (valid range: 0 to SPI_MAX_FIFO_DEPTH)

void SPI_getFIFOInterruptLevel(SPI_Type *SPIx, uint8_t *txLevel, uint8_t *rxLevel)

get FIFO interrupt level

参数:

  • SPIx –

  • txLevel –

  • rxLevel –

uint8_t SPI_getTxFIFOStatus(SPI_Type *SPIx)

get transmit data num in TX FIFO

参数:

SPIx –

返回:

SPI TxFIFO Level

uint8_t SPI_getRxFIFOStatus(SPI_Type *SPIx)

get received data num in RX FIFO

参数:

SPIx –

返回:

SPI RxFIFO Level

bool SPI_isBusy(SPI_Type *SPIx)

get spi is busy or not

参数:

SPIx –

返回:

true

返回:

false

void SPI_writeDataNonBlocking(SPI_Type *SPIx, uint16_t data)

write data in non-blocking mode

参数:

  • SPIx –

  • data –

uint16_t SPI_readDataNonBlocking(SPI_Type *SPIx)

read data in non-blocking mode

参数:

SPIx –

返回:

uint16_t

void SPI_writeDataBlockingFIFO(SPI_Type *SPIx, uint16_t data)

write data in blocking mode with FIFO status

参数:

  • SPIx –

  • data –

uint16_t SPI_readDataBlockingFIFO(SPI_Type *SPIx)

read data in blocking mode with FIFO status

参数:

SPIx –

返回:

uint16_t

void SPI_writeDataBlockingNonFIFO(SPI_Type *SPIx, uint16_t data)

write data in blocking mode with register status

参数:

  • SPIx –

  • data –

uint16_t SPI_readDataBlockingNonFIFO(SPI_Type *SPIx)

read data in blocking mode with register status

参数:

SPIx –

返回:

uint16_t

void SPI_setConfig(SPI_Type *SPIx, SPI_Config *config)

set spi configuration

参数:

  • SPIx –

  • config –

void SPI_setBaudRate(SPI_Type *SPIx, uint32_t bitRate)

set spi baud rate

参数:

  • SPIx –

  • bitRate –

void SPI_enableInterrupt(SPI_Type *SPIx, uint32_t intFlags)

enable interrupt

参数:

  • SPIx –

  • intFlags – SPI0_IMR_RSVD_IMR_Msk SPI0_IMR_MSTIM_Msk SPI0_IMR_RXFIM_Msk SPI0_IMR_RXOIM_Msk SPI0_IMR_RXUIM_Msk SPI0_IMR_TXOIM_Msk SPI0_IMR_TXEIM_Msk

void SPI_disableInterrupt(SPI_Type *SPIx, uint32_t intFlags)

disable interrupt

参数:

  • SPIx –

  • intFlags – parameters are the same as those used in SPI_enableInterrupt.

uint32_t SPI_getInterruptStatus(SPI_Type *SPIx)

get interrupt status

参数:

SPIx –

返回:

uint32_t return value is interrupt mask

void SPI_clearInterruptStatus(SPI_Type *SPIx, uint32_t intFlags)

clear interrupt status

参数:

  • SPIx –

  • intFlags – parameters are the same as those used in SPI_enableInterrupt.

void SPI_enableDMA(SPI_Type *SPIx)

enable DMA interface

参数:

SPIx –

void SPI_disableDMA(SPI_Type *SPIx)

disable DMA interface

参数:

SPIx –

void SPI_transmit24Bits(SPI_Type *SPIx, uint32_t data)

transmit 24bits data with 8bits length data

参数:

  • SPIx –

  • data –

void SPI_transmit32Bits(SPI_Type *SPIx, uint32_t data)

transmit 32bits data with 16bits length data

参数:

  • SPIx –

  • data –

uint16_t SPI_receive16Bits(SPI_Type *SPIx, SPI_endianess endianness, uint16_t dummyData)

receive 16bit with 8bit length data

参数:

  • SPIx –

  • endianness –

  • dummyData –

返回:

uint16_t

uint32_t SPI_receive24Bits(SPI_Type *SPIx, SPI_endianess endianness, uint16_t dummyData)

receive 24bit with 8bit length data

参数:

  • SPIx –

  • endianness –

  • dummyData –

返回:

uint32_t

uint32_t SPI_receive32Bits(SPI_Type *SPIx, SPI_endianess endianness, uint16_t dummyData)

receive 32bit with 8bit length data

参数:

  • SPIx –

  • endianness –

  • dummyData –

返回:

uint32_t

uint16_t SPI_pollingNonFIFOTransaction(SPI_Type *SPIx, uint16_t charLength, uint16_t data)

transmit and receive 1 data in polling mode with register status

参数:

  • SPIx –

  • charLength –

  • data –

返回:

uint16_t

void SPI_pollingFIFOTransaction(SPI_Type *SPIx, uint16_t charLength, void *pTxBuffer, void *pRxBuffer, uint16_t numOfWords)

transmit and receive [numOfWords] data in polling mode with register status

参数:

  • SPIx –

  • charLength –

  • pTxBuffer –

  • pRxBuffer –

  • numOfWords –

void SPI_enableLoopback(SPI_Type *SPIx)

Enables the loopback mode for the SPI interface.

In loopback mode, the transmitted data is internally connected to the receiver input, allowing for testing and debugging without the need for an external device.

备注

This function should be called only when the SPI interface is disabled.

参数:

SPIx – Pointer to the SPI peripheral, where x can be 0, 1, 2, or 3 to select the SPI peripheral.

void SPI_disableLoopback(SPI_Type *SPIx)

Disables the loopback mode for the SPI interface.

In loopback mode, the transmitted data is internally connected to the receiver input, allowing for testing and debugging without the need for an external device.

备注

This function should be called only when the SPI interface is disabled.

参数:

SPIx – Pointer to the SPI peripheral, where x can be 0, 1, 2, or 3 to select the SPI peripheral.

void SPI_initStruct(SPI_Config *cfg)

Initializes the SPI configuration structure.

备注

This function is used to initialize each member variable of the SPI configuration structure

参数:

cfg – Pointer to the SPI configuration structure

Structures

struct SPI_Config

Macros

SPI_INTERRUPT_ALL
SPI_CS_NONE
SPI_CS0
SPI_CS1
SPI_CS2
SPI_CS3
SPI_transmitByte(SPIx, txData)
SPI_transmit16Bits(SPIx, txData)
SPI_transmitNBytes(SPIx, txBuffer, numOfWords)
SPI_transmitN16BitWord(SPIx, txBuffer, numOfWords)
SPI_transmitNWordsWithCharLength(SPIx, charLength, txBuffer, numOfWords)
SPI_receiveByte(SPIx, dummyData)
SPI_receiveNBytes(SPIx, rxBuffer, numOfWords)
SPI_receiveN16BitWord(SPIx, rxBuffer, numOfWords)
SPI_receiveNWordsWithcharLength(SPIx, charLength, rxBuffer, numOfWords)

Enumerations

enum SPI_TransferProtocol

Values:

enumerator SPI_PROT_POL0PHA0
enumerator SPI_PROT_POL0PHA1
enumerator SPI_PROT_POL1PHA0
enumerator SPI_PROT_POL1PHA1
enum SPI_TransferMode

Values:

enumerator SPI_TRANSMIT_RECEIVE
enumerator SPI_TRANSMIT
enumerator SPI_RECEIVE
enumerator SPI_EEPROM_READ
enum SPI_endianess

Values:

enumerator SPI_DATA_LITTLE_ENDIAN
enumerator SPI_DATA_BIG_ENDIAN