使用STM32的硬件SPI及软件模拟SPI的方式驱动MAX7219点阵

开发板使用STM32F103ZET6主控，可使用其自带的硬件SPI或者使用软件模拟SPI的方式驱动MAX7219点阵，显示其他字符可在code_disp1中修改字节定义。

一、max7219.c。

在模拟SPI时，函数Write_Max7219_byte()中，对Max7219_pinDIN的定义不可写成Max7219_pinDIN = data & 0x80;实测无效（暂时不知道原因，时钟太快数据处理不过来？在51单片机中可以正常使用），上电点阵无显示或者为全亮状态。使用逻辑分析仪抓取分析，Max7219_pinDIN一直是低电平状态，导致MAX7219无数据写入。

#include "max7219.h"#include "delay.h"u8 code_disp1[38][8]={{0x3C,0x42,0x42,0x42,0x42,0x42,0x42,0x3C},//0{0x08,0x18,0x28,0x08,0x08,0x08,0x08,0x3E},//1{0x7E,0x02,0x02,0x7E,0x40,0x40,0x40,0x7E},//2{0x3E,0x02,0x02,0x3E,0x02,0x02,0x3E,0x00},//3{0x08,0x18,0x28,0x48,0xFE,0x08,0x08,0x08},//4{0x3C,0x20,0x20,0x3C,0x04,0x04,0x3C,0x00},//5{0x3C,0x20,0x20,0x3C,0x24,0x24,0x3C,0x00},//6{0x3E,0x22,0x04,0x08,0x08,0x08,0x08,0x08},//7{0x00,0x3E,0x22,0x22,0x3E,0x22,0x22,0x3E},//8{0x3E,0x22,0x22,0x3E,0x02,0x02,0x02,0x3E},//9{0x08,0x14,0x22,0x3E,0x22,0x22,0x22,0x22},//A{0x3C,0x22,0x22,0x3E,0x22,0x22,0x3C,0x00},//B{0x3C,0x40,0x40,0x40,0x40,0x40,0x3C,0x00},//C{0x7C,0x42,0x42,0x42,0x42,0x42,0x7C,0x00},//D{0x7C,0x40,0x40,0x7C,0x40,0x40,0x40,0x7C},//E{0x7C,0x40,0x40,0x7C,0x40,0x40,0x40,0x40},//F{0x3C,0x40,0x40,0x40,0x40,0x44,0x44,0x3C},//G{0x44,0x44,0x44,0x7C,0x44,0x44,0x44,0x44},//H{0x7C,0x10,0x10,0x10,0x10,0x10,0x10,0x7C},//I{0x3C,0x08,0x08,0x08,0x08,0x08,0x48,0x30},//J{0x00,0x24,0x28,0x30,0x20,0x30,0x28,0x24},//K{0x40,0x40,0x40,0x40,0x40,0x40,0x40,0x7C},//L{0x81,0xC3,0xA5,0x99,0x81,0x81,0x81,0x81},//M{0x00,0x42,0x62,0x52,0x4A,0x46,0x42,0x00},//N{0x3C,0x42,0x42,0x42,0x42,0x42,0x42,0x3C},//O{0x3C,0x22,0x22,0x22,0x3C,0x20,0x20,0x20},//P{0x1C,0x22,0x22,0x22,0x22,0x26,0x22,0x1D},//Q{0x3C,0x22,0x22,0x22,0x3C,0x24,0x22,0x21},//R{0x00,0x1E,0x20,0x20,0x3E,0x02,0x02,0x3C},//S{0x00,0x3E,0x08,0x08,0x08,0x08,0x08,0x08},//T{0x42,0x42,0x42,0x42,0x42,0x42,0x22,0x1C},//U{0x42,0x42,0x42,0x42,0x42,0x42,0x24,0x18},//V{0x00,0x49,0x49,0x49,0x49,0x2A,0x1C,0x00},//W{0x81,0x42,0x24,0x18,0x18,0x24,0x42,0x81},//X{0x41,0x22,0x14,0x08,0x08,0x08,0x08,0x08},//Y{0x00,0x7F,0x02,0x04,0x08,0x10,0x20,0x7F},//Z{0x08,0x7F,0x49,0x49,0x7F,0x08,0x08,0x08},//中{0xFE,0xBA,0x92,0xBA,0x92,0x9A,0xBA,0xFE},//国};#if SPI_IS_HARDWARE //判断SPI方式void Max7219_GPIO_Init(void)//硬件SPI{SPI_InitTypeDef SPI1_InitStructure;GPIO_InitTypeDef GPIO_InitStructure;//配置SPI1管脚RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO|RCC_APB2Periph_GPIOA, ENABLE);RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1,ENABLE);GPIO_InitStructure.GPIO_Pin=Max7219_pinCS_GPIO;//CS/LOADGPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;GPIO_InitStructure.GPIO_Mode=GPIO_Mode_Out_PP;GPIO_Init(GPIOA,&GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin=Max7219_pinCLK_GPIO|SPI_MISO_GPIO|Max7219_pinDIN_GPIO;//CLK MISO MOSI GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;GPIO_Init(GPIOA,&GPIO_InitStructure);SPI1_InitStructure.SPI_Direction=SPI_Direction_2Lines_FullDuplex;SPI1_InitStructure.SPI_BaudRatePrescaler=SPI_BaudRatePrescaler_64;SPI1_InitStructure.SPI_DataSize=SPI_DataSize_8b;SPI1_InitStructure.SPI_Mode=SPI_Mode_Master;SPI1_InitStructure.SPI_FirstBit=SPI_FirstBit_MSB; //高位在先SPI1_InitStructure.SPI_CPOL = SPI_CPOL_High;SPI1_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;SPI1_InitStructure.SPI_NSS = SPI_NSS_Soft; SPI1_InitStructure.SPI_CRCPolynomial = 7;SPI_I2S_DeInit(SPI1);SPI_Init(SPI1, &SPI1_InitStructure); SPI_Cmd(SPI1, ENABLE); }//功能：向MAX7219内部寄存器写入数据//参数：addr、datvoid Write_Max7219(u8 addr,u8 dat){Max7219_pinCS = 0;SPI_I2S_SendData(SPI1, addr); //写入地址delay_us(10);//必须，点阵不显示时可以延长此延时调试SPI_I2S_SendData(SPI1, dat); //写入数据delay_us(10);//必须，点阵不显示时可以延长此延时调试Max7219_pinCS = 1;}#elsevoid Max7219_GPIO_Init(void)//软件模拟SPI{GPIO_InitTypeDef GPIO_InitStructure;RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;GPIO_InitStructure.GPIO_Pin = Max7219_pinCS_GPIO | Max7219_pinDIN_GPIO | Max7219_pinCLK_GPIO;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOA,&GPIO_InitStructure);}//功能：向MAX7219写入字节//入口参数：datavoid Write_Max7219_byte(u8 data) {u8 i; Max7219_pinCS = 0;for(i = 0;i<8;i++){Max7219_pinCLK = 0;if((data & 0x80) == 0)//写成Max7219_pinDIN = data & 0x80;实测无效，Max7219_pinDIN一直是低电平{Max7219_pinDIN = 0;}else{Max7219_pinDIN = 1;}data = data<<1;Max7219_pinCLK = 1;}}//功能：向MAX7219内部寄存器写入数据//参数：addr、datvoid Write_Max7219(u8 addr,u8 dat){Max7219_pinCS = 0;Write_Max7219_byte(addr); //写入地址//delay_us(10);//模拟SPI时可以去除Write_Max7219_byte(dat);//写入数据//delay_us(10);Max7219_pinCS = 1; }#endifvoid Init_MAX7219(void){Write_Max7219(0x09, 0x00); //译码方式：无Write_Max7219(0x0a, 0x03); //亮度 Write_Max7219(0x0b, 0x07); //扫描界限；8个数码管显示Write_Max7219(0x0c, 0x01); //掉电模式：0，普通模式：1Write_Max7219(0x0f, 0x00); //显示测试：1；测试结束，正常显示：0}

二、max7219.h。

根据实际需求修改函数，修改定义SPI_IS_HARDWARE，确定使用硬件SPI或者软件模拟SPI。本max7219库文件中，使用的软、硬件SPI引脚为同一引脚，所以在不改变引脚的情况下，可定义SPI_IS_HARDWARE自主选择SPI方式。

#ifndef __MAX7219_H#define __MAX7219_H#include "stm32f10x.h"#include "sys.h"#define SPI_IS_HARDWARE 1 //1：硬件SPI；0：软件模拟SPI#define Max7219_pinDIN_GPIO GPIO_Pin_7#define Max7219_pinCS_GPIO GPIO_Pin_3#define Max7219_pinCLK_GPIO GPIO_Pin_5#define SPI_MISO_GPIO GPIO_Pin_6//未使用到#define Max7219_pinDIN PAout(7)#define Max7219_pinCS PAout(3)#define Max7219_pinCLK PAout(5)void Max7219_GPIO_Init(void);void Write_Max7219_byte(u8 data);void Write_Max7219(u8 addr,u8 dat);void Init_MAX7219(void);#endif

三、main.c

主函数是对code_disp1数组中的字符循环显示，在实际使用当中，如果显示字符变动不频繁可将显示函数写在while（1）之前，特别是有多个点阵级联情况下。否则会在while里循环刷新，级联状况下点阵会有重影（上一级的残影）。

另外在电源突然断开再重新上电情况下，点阵屏不显示，需要手动按下单片机复位按键方可正常显示，测试后在max7219初始化和SPI初始化之前增加延时可解决，具体延时时长可自行调试。本人使用的是国产GC7219驱动芯片（购买时图片上标的是MAX7219。。。），也有可能是芯片原因，MAX7219没有试验过，后续有机会验证。

#include "stm32f10x.h"#include "sys.h"#include "delay.h"#include "max7219.h"extern u8 code_disp1[38][8];int main(void){u8 i,j;delay_init();delay_ms(500);//只能解决短暂掉电后上电点阵不显示问题，否则需要手动按复位Max7219_GPIO_Init();delay_ms(500);Init_MAX7219();while(1){Max7219_pinCS = 1;delay_ms(1);for(j=0;j<38;j++){for(i=1;i<9;i++)Write_Max7219(i,code_disp1[j][i-1]);delay_ms(1000);} }}