Rainbow Electronics AT45DB642 - Manual (Page 10)

10 AT45DB321E [PRELIMINARY DATASHEET]
8784B–DFLASH–11/2012
6. Program and Erase Commands
6.1 Buffer Write
Utilizing the Buffer Write command allows data clocked in from the SI pin to be written directly into either one of the
SRAM data buffers.
To load data into a buffer using the standard DataFlash buffer size (528 bytes), an opcode of 84h for Buffer 1 or 87h for
Buffer 2 must be clocked into the device followed by three address bytes comprised of 14 dummy bits and 10 buffer
address bits (BFA9 - BFA0). The 10 buffer address bits specify the first byte in the buffer to be written.
To load data into a buffer using the binary buffer size (512 bytes), an opcode of 84h for Buffer 1 or 87h for Buffer 2, must
be clocked into the device followed by 15 dummy bits and nine buffer address bits (BFA8 - BFA0). The nine buffer
address bits specify the first byte in the buffer to be written.
After the last address byte has been clocked into the device, data can then be clocked in on subsequent clock cycles. If
the end of the data buffer is reached, the device will wrap around back to the beginning of the buffer. Data will continue to
be loaded into the buffer until a low-to-high transition is detected on the CS pin.
6.2 Buffer to Main Memory Page Program with Built-In Erase
The Buffer to Main Memory Page Program with Built-In Erase command allows data that is stored in one of the SRAM
buffers to be written into an erased or programmed page in the main memory array. It is not necessary to pre-erase the
page in main memory to be written because this command will automatically erase the selected page prior to the
program cycle.
To perform a Buffer to Main Memory Page Program with Built-In Erase using the standard DataFlash page size
(528 bytes), an opcode of 83h for Buffer 1 or 86h for Buffer 2 must be clocked into the device followed by three address
bytes comprised of one dummy bit, 13 page address bits (PA12 - PA0) that specify the page in the main memory to be
written, and 10 dummy bits.
To perform a Buffer to Main Memory Page Program with Built-In Erase using the binary page size (512 bytes), an opcode
of 83h for Buffer 1 or 86h for Buffer 2 must be clocked into the device followed by three address bytes comprised of two
dummy bits, 13 page address bits (A21 - A9) that specify the page in the main memory to be written, and nine dummy
bits.
When a low-to-high transition occurs on the CS pin, the device will first erase the selected page in main memory (the
erased state is a Logic 1) and then program the data stored in the appropriate buffer into that same page in main
memory. Both the erasing and the programming of the page are internally self-timed and should take place in a
maximum time of t
EP
. During this time, the RDY/BUSY bit in the Status Register will indicate that the device is busy.
The device also incorporates an intelligent erase and program algorithm that can detect when a byte location fails to
erase or program properly. If an erase or programming error arises, it will be indicated by the EPE bit in the Status
Register.
6.3 Buffer to Main Memory Page Program without Built-In Erase
The Buffer to Main Memory Page Program without Built-In Erase command allows data that is stored in one of the SRAM
buffers to be written into a pre-erased page in the main memory array. It is necessary that the page in main memory to be
written be previously erased in order to avoid programming errors.
To perform a Buffer to Main Memory Page Program without Built-In Erase using the standard DataFlash page size (528
bytes), an opcode of 88h for Buffer 1 or 89h for Buffer 2 must be clocked into the device followed by three address bytes
comprised of one dummy bit, 13 page address bits (PA12 - PA0) that specify the page in the main memory to be written,
and 10 dummy bits.
To perform a Buffer to Main Memory Page Program using the binary page size (512 bytes), an opcode of 88h for Buffer
1 or 89h for Buffer 2 must be clocked into the device followed by three address bytes comprised of two dummy bits, 13
page address bits (A21 - A9) that specify the page in the main memory to be written, and nine dummy bits.