Method writeBytes

SPIFlash.cpp:234–255

write multiple bytes to flash memory (up to 64K) WARNING: you can only write to previously erased memory locations (see datasheet) use the block erase commands to first clear memory (write 0xFFs) This version handles both page alignment and data blocks larger than 256 bytes.

/// This version handles both page alignment and data blocks larger than 256 bytes.
///
void SPIFlash::writeBytes(uint32_t addr, const void* buf, uint16_t len) {
  uint16_t n;
  uint16_t maxBytes = 256-(addr%256);  // force the first set of bytes to stay within the first page
  uint16_t offset = 0;
  while (len>0)
  {
    n = (len<=maxBytes) ? len : maxBytes;
    command(SPIFLASH_BYTEPAGEPROGRAM, true);  // Byte/Page Program
    SPI.transfer(addr >> 16);
    SPI.transfer(addr >> 8);
    SPI.transfer(addr);
    
    for (uint16_t i = 0; i < n; i++)
      SPI.transfer(((uint8_t*) buf)[offset + i]);
    unselect();
    
    addr+=n;  // adjust the addresses and remaining bytes by what we've just transferred.
    offset +=n;
    len -= n;
    maxBytes = 256;   // now we can do up to 256 bytes per loop
  }
}

/// erase entire flash memory array
/// may take several seconds depending on size, but is non blocking