基于单片机的SPI接口OLED显示-单片机中spi

8.1 原理图分析

查看EK-RA6M4的原理图，如下图所示，该开发板上的MikroBus接口上有提供一个SPI接口。

根据原理图可知，SPI接口的四个引脚分别为：

功能 引脚 MISO P202 MOSI P203 SCK P204 CS P205

这里我们将在该SPI接口上连接 SPI OLED显示屏(3.3V供电)，该OLED显示屏的接口定义如下：

引脚 功能 EK-RA6M4引脚 GND GND GND VCC 3.3V 3.3V D0 SCK P204 D1 MOSI P203 RST 复位(必须要控制 0->1) P207 DC Data(高电平)/Command(低电平) P206 CS 已接地，不用接

8.2 SPI接口配置

首先，在FSP配置中将SPI所用的两个口P203、P204配置成SPI模式。

然后，在FSP配置中将数据命令选择(DC)和两个引脚P206、P207配置成GPIO模式。

接着选择 Stacks ，点击 “New Stack” -> “Connectivity” -> “SPI(r_spi)” 添加 SPI 协议栈。

接下来设置SPI的相关配置，并重新生成代码。

通过 Name 字段可以修改SPI中断的名称为 g_spi0_master，它将在IDE自动生成的文件 ra_gen/hal_data.c/h 中定义SPI操作相关的变量； 通过 Channel 字段可以修改SPI的通道号，这里设置为0，下面的 Pins 将自动选择 P202、P203和 P204 这个引脚； 在这里选择使能所有的SPI中断并设置优先级为2级别，在这里保持默认的SPI的工作模式、工作极性等； 通过 Callback 字段设置SPI收发的中断回调函数 spi0_master_callback ，它将配置在 g_spi0_master_cfg 变量中，该函数需要我们自己实现； 通过 Full or Transmit Only Mode 字段，我们设置SPI工作在 Transmit Only 模式，这是因为我们的MCU会给OLED发送数据，而不会接收； 通过 Bitrate 字段，可以修改SPI的速率。事实上这里设置为默认的16MHz，OLED显示屏也是可以正常工作的。

6.3 源码修改

创建OLED操作相关的头文件 src/bsp_oled.h 如下：

复制#ifndef BSP_OLED_H_ #define BSP_OLED_H_ #include extern void OLED_Init(void); extern void OLED_Show_Picture(void); #endif /* BSP_OLED_H_ */

创建OLED操作相关的c文件 src/bsp_oled.c 如下：

复制#include #include #include “r_spi_api.h” #include “hal_data.h” #define RESET_VALUE 0x00 static volatile spi_event_t spi_event; // Master Transfer Event completion flag static fsp_err_t spi_init(void); static fsp_err_t spi_write(uint8_t *data, uint32_t bytes); static fsp_err_t spi_read(uint8_t *buf, uint32_t size); static inline void OLED_WrDat(uint8_t data) { R_BSP_PinWrite(oled_cd, BSP_IO_LEVEL_HIGH); spi_write(&data, 1); } static inline void OLED_WrCmd(uint8_t cmd) { R_BSP_PinWrite(oled_cd, BSP_IO_LEVEL_LOW); spi_write(&cmd, 1); } void OLED_Init() { if( FSP_SUCCESS != spi_init() ) return ; printf(“Reset and initial OLED panel “); R_BSP_PinWrite(oled_rst, BSP_IO_LEVEL_LOW); R_BSP_SoftwareDelay(10, BSP_DELAY_UNITS_MILLISECONDS); R_BSP_PinWrite(oled_rst, BSP_IO_LEVEL_HIGH); OLED_WrCmd(0xAE); //display off OLED_WrCmd(0x20); //Set Memory Addressing Mode OLED_WrCmd(0x10); //00,Horizontal Addressing Mode;01,Vertical Addressing Mode;10,Page Addressing Mode (RESET);11,Invalid OLED_WrCmd(0xb0); //Set Page Start Address for Page Addressing Mode,0-7 OLED_WrCmd(0xc8); //Set COM Output Scan Direction OLED_WrCmd(0x00);//—set low column address OLED_WrCmd(0x10);//—set high column address OLED_WrCmd(0x40);//–set start line address OLED_WrCmd(0x81);//–set contrast control register OLED_WrCmd(0x7f); OLED_WrCmd(0xa1);//–set segment re-map 0 to 127 OLED_WrCmd(0xa6);//–set normal display OLED_WrCmd(0xa8);//–set multiplex ratio(1 to 64) OLED_WrCmd(0x3F);// OLED_WrCmd(0xa4);//0xa4,Output follows RAM content;0xa5,Output ignores RAM content OLED_WrCmd(0xd3);//-set display offset OLED_WrCmd(0x00);//-not offset OLED_WrCmd(0xd5);//–set display clock divide ratio/oscillator frequency OLED_WrCmd(0xf0);//–set divide ratio OLED_WrCmd(0xd9);//–set pre-charge period OLED_WrCmd(0x22); // OLED_WrCmd(0xda);//–set com pins hardware configuration OLED_WrCmd(0x12); OLED_WrCmd(0xdb);//–set vcomh OLED_WrCmd(0x20);//0x20,0.77xVcc OLED_WrCmd(0x8d);//–set DC-DC enable OLED_WrCmd(0x14);// OLED_WrCmd(0xaf);//–turn on oled panel R_BSP_SoftwareDelay(5, BSP_DELAY_UNITS_MILLISECONDS); } /*+——————–+ *| Show Picture API | *+——————–+ */ uint8_t picture_code[]= { 0x00,0x06,0x0A,0xFE,0x0A,0xC6,0x00,0xE0,0x00,0xF0,0x00,0xF8,0x00,0x00,0x00,0x00, 0x00,0x00,0xFE,0x7D,0xBB,0xC7,0xEF,0xEF,0xEF,0xEF,0xEF,0xEF,0xEF,0xC7,0xBB,0x7D, 0xFE,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x08, 0x0C,0xFE,0xFE,0x0C,0x08,0x20,0x60,0xFE,0xFE,0x60,0x20,0x00,0x00,0x00,0x78,0x48, 0xFE,0x82,0xBA,0xBA,0x82,0xBA,0xBA,0x82,0xBA,0xBA,0x82,0xBA,0xBA,0x82,0xFE,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xFE,0xFF, 0x03,0x03,0x03,0x03,0x03,0x03,0x03,0x03,0x03,0xFF,0xFF,0x00,0x00,0xFE,0xFF,0x03, 0x03,0x03,0x03,0x03,0x03,0x03,0x03,0x03,0xFF,0xFE,0x00,0x00,0x00,0x00,0xC0,0xC0, 0xC0,0x00,0x00,0x00,0x00,0xFE,0xFF,0x03,0x03,0x03,0x03,0x03,0x03,0x03,0x03,0x03, 0xFF,0xFE,0x00,0x00,0xFE,0xFF,0x03,0x03,0x03,0x03,0x03,0x03,0x03,0x03,0x03,0xFF, 0xFE,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xFF,0xFF, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xFF,0xFF,0x00,0x00,0xFF,0xFF,0x0C, 0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0xFF,0xFF,0x00,0x00,0x00,0x00,0xE1,0xE1, 0xE1,0x00,0x00,0x00,0x00,0xFF,0xFF,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0xFF,0xFF,0x00,0x00,0xFF,0xFF,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0xFF, 0xFF,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x0F,0x1F, 0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x1F,0x0F,0x00,0x00,0x0F,0x1F,0x18, 0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x1F,0x0F,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x0F,0x1F,0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x18, 0x1F,0x0F,0x00,0x00,0x0F,0x1F,0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x1F, 0x0F,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0xE2,0x92,0x8A,0x86,0x00,0x00,0x7C,0x82,0x82,0x82,0x7C, 0x00,0xFE,0x00,0x82,0x92,0xAA,0xC6,0x00,0x00,0xC0,0xC0,0x00,0x7C,0x82,0x82,0x82, 0x7C,0x00,0x00,0x02,0x02,0x02,0xFE,0x00,0x00,0xC0,0xC0,0x00,0x7C,0x82,0x82,0x82, 0x7C,0x00,0x00,0xFE,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x24,0xA4,0x2E,0x24,0xE4,0x24,0x2E,0xA4,0x24,0x00,0x00,0x00,0xF8,0x4A,0x4C, 0x48,0xF8,0x48,0x4C,0x4A,0xF8,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xC0,0x20,0x10,0x10, 0x10,0x10,0x20,0xC0,0x00,0x00,0xC0,0x20,0x10,0x10,0x10,0x10,0x20,0xC0,0x00,0x00, 0x00,0x12,0x0A,0x07,0x02,0x7F,0x02,0x07,0x0A,0x12,0x00,0x00,0x00,0x0B,0x0A,0x0A, 0x0A,0x7F,0x0A,0x0A,0x0A,0x0B,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x1F,0x20,0x40,0x40, 0x40,0x50,0x20,0x5F,0x80,0x00,0x1F,0x20,0x40,0x40,0x40,0x50,0x20,0x5F,0x80,0x00, }; void OLED_Show_Picture(void) { unsigned char x,y; unsigned int i=0; for(y=0;y<8;y++) { OLED_WrCmd(0xb0+y); OLED_WrCmd(0x00); OLED_WrCmd(0x10); for(x=0;x<128;x++) { OLED_WrDat(picture_code[i++]); } } } /*+————–+ *| SPI API | *+————–+ */ static fsp_err_t spi_init(void) { fsp_err_t err = FSP_SUCCESS; err = R_SPI_Open (&g_spi0_master_ctrl, &g_spi0_master_cfg); if (FSP_SUCCESS != err) { printf(“** R_SPI_Open API for SPI Master failed ** “); return err; } return err; } void spi0_master_callback(spi_callback_args_t * p_args) { if (SPI_EVENT_TRANSFER_COMPLETE == p_args->event) { spi_event = SPI_EVENT_TRANSFER_COMPLETE; } else { spi_event = SPI_EVENT_TRANSFER_ABORTED; } } static inline fsp_err_t validate_spi_event(void) { uint32_t local_time_out = UINT32_MAX; while( SPI_EVENT_TRANSFER_COMPLETE != spi_event ) { –local_time_out; if(RESET_VALUE == local_time_out) { spi_event = (spi_event_t)RESET_VALUE; return FSP_ERR_TIMEOUT; } } if(spi_event == SPI_EVENT_TRANSFER_COMPLETE) { spi_event = (spi_event_t)RESET_VALUE; return FSP_SUCCESS; } spi_event = (spi_event_t)RESET_VALUE; return FSP_ERR_TRANSFER_ABORTED; } static fsp_err_t spi_write(uint8_t *data, uint32_t bytes) { fsp_err_t err = FSP_SUCCESS; /* resetting call back event capture variable */ spi_event = (spi_event_t)RESET_VALUE; err = R_SPI_Write(&g_spi0_master_ctrl, data, bytes, SPI_BIT_WIDTH_8_BITS); if(FSP_SUCCESS != err) { printf(“Master R_SPI_Write() failed “); return err; } err = validate_spi_event(); if (FSP_SUCCESS != err) { printf(“** SPI write validate failed, err=%d ** “, err); return err; } return FSP_SUCCESS; } __attribute__((unused)) static fsp_err_t spi_read(uint8_t *buf, uint32_t size) { fsp_err_t err = FSP_SUCCESS; /* resetting call back event capture variable */ spi_event = (spi_event_t)RESET_VALUE; err = R_SPI_Read(&g_spi0_master_ctrl, buf, size, SPI_BIT_WIDTH_8_BITS); if(FSP_SUCCESS != err) { printf(“Master R_SPI_Write() failed “); return err; } err = validate_spi_event(); if (FSP_SUCCESS != err) { printf(“** SPI write validate failed, err=%d ** “, err); return err; } return FSP_SUCCESS; }

修改 src/hal_entry.c 源文件，在里面添加 OLED 初始化和显示的代码。

复制… … #include “bsp_oled.h” … … void hal_entry(void) { … … OLED_Init(); OLED_Show_Picture(); while (1) { … … }

8.4 编译运行

代码修改完成后，在开发板上编译运行。这时可以看到OLED上显示图片如下：