武林教你学PIC32（十七）SPI操作M25P16 FLASH存储器

首先介绍下TI的M25P16，它是16Mbit(2Mbyte)的FLASH存储器，与常用的华邦公司的W25X16，ATMEL公司的AT51DB161比较接近。最高支持50M的SPI时钟，存储器可以以1到256字节byte，使用页编程操作将2M的容量分为32个块（Block），每个块含有256页，每页里有256字节宽带，因此整个存储器包含8192页或者2，097，152字节。操作命令为：

我们根据这些命令，做好下面封装函数：

//需要外接函数

extern unsigned char SPI_FLASH_SendByte(unsigned char ch);

extern unsigned char SPI_FLASH_ReadByte(unsigned char ch);

//高级函数

u32 SPI_FLASH_ReadID(void);//读取芯片ID正确发回0X202015

u8 SPI_FLASH_ByteRead(u32 ReadAddr);//读一个数据

void SPI_FLASH_BufferRead(u8* pBuffer, u32 ReadAddr, u16 NumByteToRead);

void SPI_FLASH_PageWrite(u8* pBuffer, u32 WriteAddr, u16 NumByteToWrite);//页写

void SPI_FLASH_BufferWrite(u8* pBuffer, u32 WriteAddr, u16 NumByteToWrite);

void SPI_FLASH_SectorErase(u32 SectorAddr);//扇区擦除

void SPI_FLASH_BulkErase(void);//全部擦除

void SPI_Flash_PowerDown(void); //进入掉电模式

void SPI_Flash_WAKEUP(void);//唤醒

//底层函数

void SPI_FLASH_WriteEnable(void);

void SPI_FLASH_WriteDisable(void);

void SPI_FLASH_WaitForWriteEnd(void);

我们申请到的FLASH模块与SPI2连接，如图所示：

主函数里面实现这样的测试功能：首先测试芯片的型号，看是不是TI M25P16芯片，然后擦除扇区，再写入要测试的数据，最后读回来看是不是这些内容。

主函数代码：

#include "usart2.h"

#include "spi2.h"

#include "m25p16.h"

#include "led.h"

/* Private typedef -----------------------------------------------------------*/

typedef enum {FAILED = 0, PASSED = !FAILED} TestStatus;

/* Private define ------------------------------------------------------------*/

#defineFLASH_WriteAddress0x00100

#defineFLASH_ReadAddressFLASH_WriteAddress

#defineFLASH_SectorToEraseFLASH_WriteAddress

#definesFLASH_ID0x202015

#defineBufferSize (countof(Tx_Buffer)-1)

/* Private macro -------------------------------------------------------------*/

#define countof(a) (sizeof(a) / sizeof(*(a)))

/* Private variables ---------------------------------------------------------*/

uint8_t Tx_Buffer[] = "nr欢迎访问EEFOUCS MIPS社区http://mips.eefocus.com/bbs/index_list.htmlrn SPI Flash Test Example: communication with an TI M25P16 SPI FLASHrn";

uint8_t Index, Rx_Buffer[BufferSize];

volatile TestStatus TransferStatus1 = FAILED, TransferStatus2 = PASSED;

uint32_t FlashID = 0;

/* Private function prototypes -----------------------------------------------*/

TestStatus Buffercmp(uint8_t *pBuffer1, uint8_t *pBuffer2, uint16_t BufferLength);

int main(void)

{

usart2_init(9600);

init_spi2();

LED_INIT();

/* Get SPI Flash Device ID */

FlashID = SPI_FLASH_ReadID();

printf("rn Device ID is 0x%X rn", FlashID);

if (FlashID == sFLASH_ID)

{

/* Turn on LED1 */

LED1_ON();//表明检测到FLASH芯片

printf("rn ST M25P16 Identitied!rn");

/* Perform a write in the Flash followed by a read of the written data */

/* Erase SPI FLASH Sector to write on */

SPI_FLASH_SectorErase(FLASH_SectorToErase);

printf("Tx_Buffer:%s", Tx_Buffer);

/* Write Tx_Buffer data to SPI FLASH memory */

SPI_FLASH_BufferWrite(Tx_Buffer, FLASH_WriteAddress, BufferSize);

/* Read data from SPI FLASH memory */

SPI_FLASH_BufferRead(Rx_Buffer, FLASH_ReadAddress, BufferSize);

printf("Rx_Buffer:%s", Rx_Buffer);

/* Check the corectness of written dada */

TransferStatus1 = Buffercmp(Tx_Buffer, Rx_Buffer, BufferSize);

/* Perform an erase in the Flash followed by a read of the written data */

/* Erase SPI FLASH Sector to write on */

SPI_FLASH_SectorErase(FLASH_SectorToErase);

/* Read data from SPI FLASH memory */

SPI_FLASH_BufferRead(Rx_Buffer, FLASH_ReadAddress, BufferSize);

/* Check the corectness of erasing operation dada */

for (Index = 0; Index < BufferSize; Index++)

{

if (Rx_Buffer[Index] != 0xFF)//因为擦除后都为0XFF

{

TransferStatus2 = FAILED;

break;

}

}

/* TransferStatus2 = PASSED, if the specified sector part is erased */

/* TransferStatus2 = FAILED, if the specified sector part is not well erased */

if((PASSED == TransferStatus1) && (PASSED == TransferStatus2))

{

/* OK: Turn on LED2 */

LED2_ON();

printf("rn M25P16 Test Suceed!nr");

}

else

{

LED4_ON();

printf("rn -->Failed: M25P16 Test Failed!nr");

}

}

else

{

/* Error: Turn on LED3 */

LED3_ON();

printf("rn M25P16 not detected!nr");

}

while(1);

}

TestStatus Buffercmp(uint8_t *pBuffer1, uint8_t *pBuffer2, uint16_t BufferLength)

{

while(BufferLength--)

{

if(*pBuffer1 != *pBuffer2)

{

return FAILED;

}

pBuffer1++;

pBuffer2++;

}

return PASSED;

}