Rainbow Electronics AT45DQ321 - Manual (Page 14)

14 AT45DQ321 [ADVANCE DATASHEET]
DS-45DQ321-031–DFLASH–12/2012
6.6 Main Memory Page Program through Buffer with Built-In Erase
The Main Memory Page Program through Buffer with Built-In Erase command combines the Buffer Write and Buffer to
Main Memory Page Program with Built-In Erase operations into a single operation to help simplify application firmware
development. With the Main Memory Page Program through Buffer with Built-In Erase command, data is first clocked
into either Buffer 1 or Buffer 2, the addressed page in memory is then automatically erased, and then the contents of the
appropriate buffer are programmed into the just-erased main memory page.
To perform a Main Memory Page Program through Buffer using the standard DataFlash page size (528 bytes), an
opcode of 82h for Buffer 1 or 85h for Buffer 2 must first be clocked into the device followed by three address bytes
comprised of 1 dummy bit, 13 page address bits (PA12 - PA0) that specify the page in the main memory to be written,
and 10 buffer address bits (BFA9 - BFA0) that select the first byte in the buffer to be written.
To perform a Main Memory Page Program through Buffer using the binary page size (512 bytes), an opcode of 82h for
Buffer 1 or 85h for Buffer 2 must first be clocked into the device followed by three address bytes comprised of 2 dummy
bits, 13 page address bits (A21 - A9) that specify the page in the main memory to be written, and 9 buffer address bits
(BFA8 - BFA0) that select the first byte in the buffer to be written.
After all address bytes have been clocked in, the device will take data from the input pin (SI) and store it in the specified
data buffer. If the end of the buffer is reached, the device will wrap around back to the beginning of the buffer. When
there is a low-to-high transition 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 buffer into that main memory page. 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 programming algorithm that can detect when a byte location fails to
erase or program properly. If an erase or program error arises, it will be indicated by the EPE bit in the Status Register.
6.7 Main Memory Byte/Page Program through Buffer 1 without Built-In Erase
The Main Memory Byte/Page Program through Buffer 1 without Built-In Erase command combines both the Buffer Write
and Buffer to Main Memory Program without Built-In Erase operations to allow any number of bytes (1 to 512/528 bytes)
to be programmed directly into previously erased locations in the main memory array. With the Main Memory Byte/Page
Program through Buffer 1 without Built-In Erase command, data is first clocked into Buffer 1, and then only the bytes
clocked into the buffer are programmed into the pre-erased byte locations in main memory. Multiple bytes up to the page
size can be entered with one command sequence.
To perform a Main Memory Byte/Page Program through Buffer 1 using the standard DataFlash page size (528 bytes), an
opcode of 02h must first be clocked into the device followed by three address bytes comprised of 1 dummy bit,
13 page address bits (PA12 - PA0) that specify the page in the main memory to be written, and 10 buffer address bits
(BFA9 - BFA0) that select the first byte in the buffer to be written. After all address bytes are clocked in, the device will
take data from the input pin (SI) and store it in Buffer 1. Any number of bytes (1 to 528) can be entered. If the end of the
buffer is reached, then the device will wrap around back to the beginning of the buffer.
To perform a Main Memory Byte/Page Program through Buffer 1 using the binary page size (512 bytes), an opcode of
02h for Buffer 1 using must first be clocked into the device followed by three address bytes comprised of 2 dummy bits,
13 page address bits (A21 - A9) that specify the page in the main memory to be written, and 9 buffer address bits (BFA8
- BFA0) that selects the first byte in the buffer to be written. After all address bytes are clocked in, the device will take
data from the input pin (SI) and store it in Buffer 1. Any number of bytes (1 to 512) can be entered. If the end of the buffer
is reached, then the device will wrap around back to the beginning of the buffer. When using the binary page size, the
page and buffer address bits correspond to a 22-bit logical address (A21-A0) in the main memory.
After all data bytes have been clocked into the device, a low-to-high transition on the CS pin will start the program
operation in which the device will program the data stored in Buffer 1 into the main memory array. Only the data bytes
that were clocked into the device will be programmed into the main memory.
Example: If only two data bytes were clocked into the device, then only two bytes will be programmed into main
memory and the remaining bytes in the memory page will remain in their previous state.