bool at45dbx_read_byte_open(uint32_t ad)
{
uint32_t addr;
if (at45dbx_check_address(ad) == false) {
return false;
}
// Set the global memory pointer to a byte address.
at45dbx_gl_ptr_mem = ad;
// If the DF memory is busy, wait until it's ready.
if (at45dbx_busy) at45dbx_wait_ready();
at45dbx_busy = false;
// Select the DF memory at45dbx_gl_ptr_mem points to.
at45dbx_chipselect_df(at45dbx_gl_ptr_mem >> AT45DBX_MEM_SIZE, true);
// Initiate a page read at a given sector.
// Send the Main Memory Page Read command.
at45dbx_spi_write_byte(AT45DBX_CMDA_RD_PAGE);
// Send the three address bytes, which comprise:
// - (24 - (AT45DBX_PAGE_ADDR_BITS + AT45DBX_BYTE_ADDR_BITS)) reserved bits;
// - then AT45DBX_PAGE_ADDR_BITS bits specifying the page in main memory to be read;
// - then AT45DBX_BYTE_ADDR_BITS bits specifying the starting byte address within that page.
// NOTE: The bits of at45dbx_gl_ptr_mem above the AT45DBX_MEM_SIZE bits are useless for the local
// DF addressing. They are used for DF discrimination when there are several DFs.
addr = (Rd_bitfield(at45dbx_gl_ptr_mem, (uint32_t)AT45DBX_MSK_PTR_PAGE) << AT45DBX_BYTE_ADDR_BITS) |
Rd_bitfield(at45dbx_gl_ptr_mem, AT45DBX_MSK_PTR_BYTE);
at45dbx_spi_write_byte(LSB2W(addr));
at45dbx_spi_write_byte(LSB1W(addr));
at45dbx_spi_write_byte(LSB0W(addr));
// Send 32 don't care clock cycles to initialize the read operation.
at45dbx_spi_write_byte(0x55);
at45dbx_spi_write_byte(0x55);
at45dbx_spi_write_byte(0x55);
at45dbx_spi_write_byte(0x55);
return true;
}
Bool at45dbx_read_open(U32 sector)
{
U32 addr;
// Set the global memory pointer to a byte address.
gl_ptr_mem = sector << AT45DBX_SECTOR_BITS; // gl_ptr_mem = sector * AT45DBX_SECTOR_SIZE.
// If the DF memory is busy, wait until it's ready.
if (at45dbx_busy) at45dbx_wait_ready();
at45dbx_busy = FALSE;
// Select the DF memory gl_ptr_mem points to.
at45dbx_chipselect_df(gl_ptr_mem >> AT45DBX_MEM_SIZE, TRUE);
// Initiate a page read at a given sector.
// Send the Main Memory Page Read command.
spi_write(AT45DBX_SPI, AT45DBX_CMDA_RD_PAGE);
// Send the three address bytes, which comprise:
// - (24 - (AT45DBX_PAGE_ADDR_BITS + AT45DBX_BYTE_ADDR_BITS)) reserved bits;
// - then AT45DBX_PAGE_ADDR_BITS bits specifying the page in main memory to be read;
// - then AT45DBX_BYTE_ADDR_BITS bits specifying the starting byte address within that page.
// NOTE: The bits of gl_ptr_mem above the AT45DBX_MEM_SIZE bits are useless for the local
// DF addressing. They are used for DF discrimination when there are several DFs.
addr = (Rd_bitfield(gl_ptr_mem, AT45DBX_MSK_PTR_PAGE) << AT45DBX_BYTE_ADDR_BITS) |
Rd_bitfield(gl_ptr_mem, AT45DBX_MSK_PTR_BYTE);
spi_write(AT45DBX_SPI, LSB2W(addr));
spi_write(AT45DBX_SPI, LSB1W(addr));
spi_write(AT45DBX_SPI, LSB0W(addr));
// Send 32 don't care clock cycles to initialize the read operation.
spi_write_dummy();
spi_write_dummy();
spi_write_dummy();
spi_write_dummy();
return OK;
}
