PIC18上的多个SPI配置

Question

我使用的是MPLABX微控制器，MPLABX2.3和XC8。我的目标是使用单个SPI硬件外设，在芯片选择时使用各种GPIO引脚与多个设备接口。我有一个LCD和一个SD卡，都需要与MCU通信(obv不是同时)。我的问题是当我尝试更改SPI硬件配置寄存器以在设备之间切换时。所以我试着减少这个问题，并得出了以下结论：

如果我只使用一个spi配置来驱动屏幕，它就可以工作。但是，如果我尝试关闭spi连接，然后重新打开相同spi连接，则屏幕不起作用。我认为问题出在mcc生成的SPI1_Open()中。

spi1.h：

#ifndef SPI1_MASTER_H
#define SPI1_MASTER_H

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>

/* SPI interfaces */
typedef enum { 
    SPI1_DEFAULT
} spi1_modes_t;

void SPI1_Initialize(void);
bool SPI1_Open(spi1_modes_t spi1UniqueConfiguration);
void SPI1_Close(void);
uint8_t SPI1_ExchangeByte(uint8_t data);
void SPI1_ExchangeBlock(void *block, size_t blockSize);
void SPI1_WriteBlock(void *block, size_t blockSize);
void SPI1_ReadBlock(void *block, size_t blockSize);
void SPI1_WriteByte(uint8_t byte);
uint8_t SPI1_ReadByte(void);

#endif //SPI1_H

spi1.c：

#include "spi1.h"
#include <xc.h>

typedef struct { 
    uint8_t con0; 
    uint8_t con1; 
    uint8_t con2; 
    uint8_t baud; 
    uint8_t operation;
} spi1_configuration_t;


//con0 == SPIxCON0, con1 == SPIxCON1, con2 == SPIxCON2, baud == SPIxBAUD, operation == Master/Slave
static const spi1_configuration_t spi1_configuration[] = {   
    { 0x3, 0x60, 0x2, 0x3, 0 }
};

void SPI1_Initialize(void)
{
    //EN disabled; LSBF MSb first; MST bus master; BMODE every byte; 
    SPI1CON0 = 0x03;
    //SMP Middle; CKE Active to idle; CKP Idle:High, Active:Low; FST disabled; SSP active high; SDIP active high; SDOP active high; 
    SPI1CON1 = 0x60;
    //SSET disabled; TXR required for a transfer; RXR data is not stored in the FIFO; 
    SPI1CON2 = 0x02;
    //CLKSEL FOSC; 
    SPI1CLK = 0x00;
    //BAUD 3; 
    SPI1BAUD = 0x03;
    TRISCbits.TRISC1 = 0;
}

bool SPI1_Open(spi1_modes_t spi1UniqueConfiguration)
{
    if(!SPI1CON0bits.EN)
    {
        SPI1CON0 = spi1_configuration[spi1UniqueConfiguration].con0;
        SPI1CON1 = spi1_configuration[spi1UniqueConfiguration].con1;
        SPI1CON2 = spi1_configuration[spi1UniqueConfiguration].con2 | (_SPI1CON2_SPI1RXR_MASK | _SPI1CON2_SPI1TXR_MASK);
        SPI1CLK  = 0x00;
        SPI1BAUD = spi1_configuration[spi1UniqueConfiguration].baud;        
        TRISCbits.TRISC1 = spi1_configuration[spi1UniqueConfiguration].operation;
        SPI1CON0bits.EN = 1;
        return true;
    }
    return false;
}

void SPI1_Close(void)
{
    SPI1CON0bits.EN = 0;
}

uint8_t SPI1_ExchangeByte(uint8_t data)
{
    SPI1TCNTL = 1;
    SPI1TXB = data;
    while(!PIR2bits.SPI1RXIF);
    return SPI1RXB;
}

void SPI1_ExchangeBlock(void *block, size_t blockSize)
{
    uint8_t *data = block;
    while(blockSize--)
    {
        SPI1TCNTL = 1;
        SPI1TXB = *data;
        while(!PIR2bits.SPI1RXIF);
        *data++ = SPI1RXB;
    }
}

// Half Duplex SPI Functions
void SPI1_WriteBlock(void *block, size_t blockSize)
{
    uint8_t *data = block;
    while(blockSize--)
    {
        SPI1_ExchangeByte(*data++);
    }
}

void SPI1_ReadBlock(void *block, size_t blockSize)
{
    uint8_t *data = block;
    while(blockSize--)
    {
        *data++ = SPI1_ExchangeByte(0);
    }
}

void SPI1_WriteByte(uint8_t byte)
{
    SPI1TXB = byte;
}

uint8_t SPI1_ReadByte(void)
{
    return SPI1RXB;
}

main.c：

#include "mcc_generated_files/mcc.h"
#include "ST7735.h"

#define led0 PORTAbits.RA7
#define led1 PORTAbits.RA6
#define led2 PORTAbits.RA5
#define led3 PORTAbits.RA4

void main(void)
{
    // Initialize the device
    SYSTEM_Initialize();
    
    led0 = SPI1_Open(SPI1_DEFAULT);
    led0 = SPI1CON0bits.EN;
    
    LCD_RESET = 1;
    delay_us(500);
    LCD_RESET = 0;
    delay_us(500);
    LCD_RESET = 1;
    delay_us(500);
    
    __delay_ms(1000);
    
    ST7735_initR();
    ST7735_fillScreen(ST7735_BLACK);

    while (1)
    {
        // Add your application code
    }
}

我也可以包括ST7735.h/ST7735.c中的内容，但我确信它们是好的，因为它们在正常配置spi1的情况下工作得很好。只有当我尝试切换spi配置时，这种糟糕的行为才会开始，为了不可避免地在多个设备之间切换，我必须这样做。在上面的代码中，SPI默认为EN=0。我可以包含SPI缺省为EN=1的版本，并使用SPI1_Close()将其关闭。然而，这两个版本的行为是相同的，并且这个版本稍微简单一些。我非常感谢您可能提出的任何意见。

Answer 1

我自己解决了这个问题。

这是令人不快的函数：

bool SPI1_Open(spi1_modes_t spi1UniqueConfiguration)
{
    if(!SPI1CON0bits.EN)
    {
        SPI1CON0 = spi1_configuration[spi1UniqueConfiguration].con0;
        SPI1CON1 = spi1_configuration[spi1UniqueConfiguration].con1;
        SPI1CON2 = spi1_configuration[spi1UniqueConfiguration].con2 | (_SPI1CON2_SPI1RXR_MASK | _SPI1CON2_SPI1TXR_MASK);
        SPI1CLK  = 0x00;
        SPI1BAUD = spi1_configuration[spi1UniqueConfiguration].baud;        
        TRISCbits.TRISC1 = spi1_configuration[spi1UniqueConfiguration].operation;
        SPI1CON0bits.EN = 1;
        return true;
    }
    return false;
}

这行代码：

SPI1CON2 = spi1_configuration[spi1UniqueConfiguration].con2 | (_SPI1CON2_SPI1RXR_MASK | _SPI1CON2_SPI1TXR_MASK);

应该是：

SPI1CON2 = spi1_configuration[spi1UniqueConfiguration].con2;

在查看initialize函数时，这一点变得很明显，该函数在默认状态为enable (即SPI1CON0 =0x83)时工作：

void SPI1_Initialize(void)
{
    //EN disabled; LSBF MSb first; MST bus master; BMODE every byte; 
    SPI1CON0 = 0x03;
    //SMP Middle; CKE Active to idle; CKP Idle:High, Active:Low; FST disabled; SSP active high; SDIP active high; SDOP active high; 
    SPI1CON1 = 0x60;
    //SSET disabled; TXR required for a transfer; RXR data is not stored in the FIFO; 
    SPI1CON2 = 0x02;
    //CLKSEL FOSC; 
    SPI1CLK = 0x00;
    //BAUD 3; 
    SPI1BAUD = 0x03;
    TRISCbits.TRISC1 = 0;
} 

此函数可以正常工作，但不能与(_SPI1CON2_SPI1RXR_MASK | _SPI1CON2_SPI1TXR_MASK)进行“或”SPI1CON2。

经过测试，它的行为是正确的。感谢奥列格·马祖罗夫，他的评论让我重新检查了mcc生成的代码。虽然mcc生成的代码以前从未让我失望过，但如果您正在使用mcc做任何足够高级的工作，我建议您在假定它正常工作之前仔细检查它。