ESP32的VSPI和HSPI

2024-07-12 17:03| 来源: 网络整理| 查看: 265

说明

SPI共有4根线，MOSI、MISO、CS、CLK，在ESP32中对应规则如下表：在这里插入图片描述 ESP32共有4个SPI，但是用户能够使用的只有2个SPI，分为VSPI和HSPI。

引脚接口

在ESP32的数据手册中，说明了VSPI和HSPI对应的引脚：

VSPI：

HSPI：

但是比较麻烦的是，ESP官方不知道犯了什么SB毛病，非弄出来个没有丝毫用途的Strapping 管脚，稍不注意，上电瞬间Strapping管脚电平不对，就没法正常启动，导致但凡是有Strapping管脚功能的引脚，大家都不敢使用。在SPI中也是这样，VSPI和HSPI默认的引脚中，都有作为Strapping管脚的引脚。我们要格外格外的小心。在这里插入图片描述

结合Strapping管脚，将引脚对应整理如下表：

VSPI 引脚功能备注IO23MOSIIO19MISOIO18CLKIO5CSStrapping管脚，上电瞬间必须保证上拉 HSPI 引脚功能备注IO13MOSIIO12MISOStrapping管脚，上电瞬间必须保证下拉IO14CLKIO15CSStrapping管脚，上电瞬间必须保证上拉更改Auduino框架中SPI默认的引脚

在用arduino框架时，其默认的SPI引脚如下：在这里插入图片描述

除了使用默认的引脚之外，还可以使用其他方式更改默认引脚。官方给出的示例如下：

/* The ESP32 has four SPi buses, however as of right now only two of * them are available to use, HSPI and VSPI. Simply using the SPI API * as illustrated in Arduino examples will use VSPI, leaving HSPI unused. * * However if we simply intialise two instance of the SPI class for both * of these buses both can be used. However when just using these the Arduino * way only will actually be outputting at a time. * * Logic analyser capture is in the same folder as this example as * "multiple_bus_output.png" * * created 30/04/2018 by Alistair Symonds */ #include // Define ALTERNATE_PINS to use non-standard GPIO pins for SPI bus #ifdef ALTERNATE_PINS #define VSPI_MISO 2 #define VSPI_MOSI 4 #define VSPI_SCLK 0 #define VSPI_SS 33 #define HSPI_MISO 26 #define HSPI_MOSI 27 #define HSPI_SCLK 25 #define HSPI_SS 32 #else #define VSPI_MISO MISO #define VSPI_MOSI MOSI #define VSPI_SCLK SCK #define VSPI_SS SS #define HSPI_MISO 12 #define HSPI_MOSI 13 #define HSPI_SCLK 14 #define HSPI_SS 15 #endif #if CONFIG_IDF_TARGET_ESP32S2 || CONFIG_IDF_TARGET_ESP32S3 #define VSPI FSPI #endif static const int spiClk = 1000000; // 1 MHz //uninitalised pointers to SPI objects SPIClass * vspi = NULL; SPIClass * hspi = NULL; void setup() { //initialise two instances of the SPIClass attached to VSPI and HSPI respectively vspi = new SPIClass(VSPI); hspi = new SPIClass(HSPI); //clock miso mosi ss #ifndef ALTERNATE_PINS //initialise vspi with default pins //SCLK = 18, MISO = 19, MOSI = 23, SS = 5 vspi->begin(); #else //alternatively route through GPIO pins of your choice vspi->begin(VSPI_SCLK, VSPI_MISO, VSPI_MOSI, VSPI_SS); //SCLK, MISO, MOSI, SS #endif #ifndef ALTERNATE_PINS //initialise hspi with default pins //SCLK = 14, MISO = 12, MOSI = 13, SS = 15 hspi->begin(); #else //alternatively route through GPIO pins hspi->begin(HSPI_SCLK, HSPI_MISO, HSPI_MOSI, HSPI_SS); //SCLK, MISO, MOSI, SS #endif //set up slave select pins as outputs as the Arduino API //doesn't handle automatically pulling SS low pinMode(vspi->pinSS(), OUTPUT); //VSPI SS pinMode(hspi->pinSS(), OUTPUT); //HSPI SS } // the loop function runs over and over again until power down or reset void loop() { //use the SPI buses spiCommand(vspi, 0b01010101); // junk data to illustrate usage spiCommand(hspi, 0b11001100); delay(100); } void spiCommand(SPIClass *spi, byte data) { //use it as you would the regular arduino SPI API spi->beginTransaction(SPISettings(spiClk, MSBFIRST, SPI_MODE0)); digitalWrite(spi->pinSS(), LOW); //pull SS slow to prep other end for transfer spi->transfer(data); digitalWrite(spi->pinSS(), HIGH); //pull ss high to signify end of data transfer spi->endTransaction(); }

实际的两块arduino设备进行spi通信代码如下： arduino进行spi通信

参考： ESP32官网spi代码 Arduino spi帮助

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