[嵌入式TDD实战]TDD开发AT26DF驱动模块(五)：模块写完

前言

在上一章中，我们写出了第二个接口并在测试用例的保障下进行了重构。接下来的事就很程序化了。查看下一个操作的文档，写测试，实现接口。

流水账

ProgramInPage

分页内编程的接口，操作符后3字节地址，然后一直传要写入的字节。

别看文档上介绍了一堆机制，其实咱在写这个接口时并不关心，因为这是很底层的接口，只提供操作的抽象，具体怎么应用这些机制咱不负责。唯一需要关心下的是256字节的上限，如果超过256字节时会有一些异常啥的话可能我们需要检查下参数。但是阅读文档发现超过了并没有关系，只是会在芯片内部缓冲区覆盖前面写入的。那就无所谓了。

没什么好说的，测试，实现，完成。。。

AT26DF.h

// description: allows anywhere from a single byte of data to 256 bytes of data to be programmed
//              into previously erased memory locations. 
// parameter  : addr   the starting address
//              buf    data buffer.
//              len    the length of data you want to write.
// return     : 
// note       : if data goes beyond the end of the page will wrap around back to the beginning 
//              of the same page. So, only the last 256 bytes(size of a page) will be programmed
//              into the page specified by addr.
void AT26DF_programInPage(AT26DF_ADDR addr, const uint8_t *buf, uint16_t len);

AT26DFTest.c

TEST(AT26DF, 0LenOrBufNULLDoNothing){
   
   
  ……
  AT26DF_programInPage(anyAddr,buf,0);
  AT26DF_programInPage(anyAddr,NULL,1);
}

TEST(AT26DF, programInPage){
   
   
  AT26DF_ADDR startAddr = 0x3434;
  SPI_SelectCS_Expect();
  SPI_writeByte_Expect(AT26DF_OPC_PROGRAM);
  _WriteAddrExpect(startAddr);
  for(i = 0; i < len; i++)
    SPI_writeByte_Expect(expectData[i]);
  SPI_DeselectCS_Expect();

  AT26DF_programInPage(startAddr,expectData,len);
}

AT26DF.c

void AT26DF_programInPage(AT26DF_ADDR addr, const uint8_t *buf, uint16_t len){
   
   
  if(buf == NULL || len == 0)
    return;
  _csSel();
  _spiWrite(AT26DF_OPC_PROGRAM);
  _writeAddr(addr);
  _spiBurstWrite(buf,len);
  _csDesel();
}

BlockErase

擦除扇区，有点意思，有三种擦除模式，因此我们的接口可能得给三个。当然也可以多加一个参数来指定是哪一个，但我就是觉得给三个比较好。这个操作很简单，就是操作码加地址。

AT26DF.h

……
#define AT26DF_OPC_BLOCKERASE_4KB     0x20
#define AT26DF_OPC_BLOCKERASE_32KB    0x52
#define AT26DF_OPC_BLOCKERASE_64KB    0xD8
……
// description: Erase a block of 4K-, 32K-, or 64K-bytes
// parameter  : addr   any address in the block to be erased.
// return     : 
// note       : Before a Block Erase command can be started, the WriteEnable command must have
//              been previously issued to the device to set the WEL bit of the Status Register 
//              to a logical “1” state.
//              for a 4K-byte erase, address bits A11-A0 will be ignored by the device and their
//              values can be either a logical “1” or “0”. For a 32K-byte erase, address bits
//              A14-A0 will be ignored, and for a 64K-byte erase, address bits A15-A0 will be
//              ignored by the device.
void AT26DF_blockErase4KB(AT26DF_ADDR addr);
void AT26DF_blockErase32KB(AT26DF_ADDR addr);
void AT26DF_blockErase64KB(AT26DF_ADDR addr);

AT26DFTest.c

……
TEST(AT26DF, blockErase4KB){
   
   
  AT26DF_ADDR startAddr = 0x34dfa;
  SPI_SelectCS_Expect();
  SPI_writeByte_Expect(AT26DF_OPC_BLOCKERASE_4KB);
  _WriteAddrExpect(startAddr);
  SPI_DeselectCS_Expect();

  AT26DF_blockErase4KB(startAddr);
}

TEST(AT26DF, blockErase32KB){
   
   
  AT26DF_ADDR startAddr = 0x34dfa;
  SPI_SelectCS_Expect();
  SPI_writeByte_Expect(AT26DF_OPC_BLOCKERASE_32KB);
  _WriteAddrExpect(startAddr);
  SPI_DeselectCS_Expect();

  AT26DF_blockErase32KB(startAddr);
}

TEST(AT26DF, blockErase64KB){
   
   
  AT26DF_ADDR startAddr = 0x34dfa;
  SPI_SelectCS_Expect();
  SPI_writeByte_Expect(AT26DF_OPC_BLOCKERASE_64KB);
  _WriteAddrExpect(startAddr);
  SPI_DeselectCS_Expect();

  AT26DF_blockErase64KB(startAddr);
}

AT26DF.c

……
void AT26DF_blockErase4KB(AT26DF_ADDR addr){
   
   
  _csSel();
  _spiWrite(AT26DF_OPC_BLOCKERASE_4KB);
  _writeAddr(addr);
  _csDesel();
}

void AT26DF_blockErase32KB(AT26DF_ADDR addr){
   
   
  _csSel();
  _spiWrite(AT26DF_OPC_BLOCKERASE_32KB);
  _writeAddr(addr);
  _csDesel();
}

void AT26DF_blockErase64KB(AT26DF_ADDR addr){
   
   
  _csSel();
  _spiWrite(AT26DF_OPC_BLOCKERASE_64KB);
  _writeAddr(addr);
  _csDesel();
}

哦，明显的冗余。让我们来提取下。

AT26DFTest.c

……
static AT26DF_ADDR startAddr