AT25SF321 datasheet(16/48 Pages) DIALOG

16 / 48 page

AT25SF321

DS-25SF321–047F–8/2017

that is sent to the device that goes beyond the end of the page will wrap around back to the beginning of the same page.

For example, if the starting address denoted by A23-A0 is 0000FEh, and three bytes of data are sent to the device, then

the first two bytes of data will be programmed at addresses 0000FEh and 0000FFh while the last byte of data will be

programmed at address 000000h. The remaining bytes in the page (addresses 000001h through 0000FDh) will not be

programmed and will remain in the erased state (FFh). In addition, if more than 256 bytes of data are sent to the device,

then only the last 256 bytes sent will be latched into the internal buffer.

When the CS pin is deasserted, the device will take the data stored in the internal buffer and program it into the

appropriate memory array locations based on the starting address specified by A23-A0 and the number of data bytes

sent to the device. If less than 256 bytes of data were sent to the device, then the remaining bytes within the page will not

be programmed and will remain in the erased state (FFh). The programming of the data bytes is internally self-timed and

should take place in a time of tPP or tBP if only programming a single byte.

The three address bytes and at least one complete byte of data must be clocked into the device before the CS pin is

deasserted, and the CS pin must be deasserted on even byte boundaries (multiples of eight bits); otherwise, the device

will abort the operation and no data will be programmed into the memory array. In addition, if the memory is in the

protected state (see “Non-Volatile Protection” on page 21), then the Byte/Page Program command will not be executed,

and the device will return to the idle state once the CS pin has been deasserted. The WEL bit in the Status Register will

be reset back to the logical “0” state if the program cycle aborts due to an incomplete address being sent, an incomplete

byte of data being sent, the CS pin being deasserted on uneven byte boundaries, or because the memory location to be

programmed is protected.

While the device is programming, the Status Register can be read and will indicate that the device is busy. For faster

throughput, it is recommended that the Status Register be polled rather than waiting the tBP or tPP time to determine if the

data bytes have finished programming. At some point before the program cycle completes, the WEL bit in the Status

Figure 7-1. Byte Program

Figure 7-2. Page Program

AT25SF321 Datasheet(PDF) 16 Page - Dialog Semiconductor