6
3597H–DFLASH–02/07
AT45DB321D [Preliminary]
Continuous Array Read, the device will continue reading at the beginning of the next page with
no delays incurred during the page boundary crossover (the crossover from the end of one page
to the beginning of the next page). When the last bit in the main memory array has been read,
the device will continue reading back at the beginning of the first page of memory. As with cross-
ing over page boundaries, no delays will be incurred when wrapping around from the end of the
array to the beginning of the array.
A low-to-high transition on the CS
pin will terminate the read operation and tri-state the output
pin (SO). The maximum SCK frequency allowable for the Continuous Array Read is defined by
the f
CAR1
specification. The Continuous Array Read bypasses both data buffers and leaves the
contents of the buffers unchanged.
6.2 Continuous Array Read (High Frequency Mode: 0BH): Up to 66 MHz
This command can be used with the serial interface to read the main memory array sequentially
in high speed mode for any clock frequency up to the maximum specified by f
CAR1
. To perform a
continuous read array with the page size set to 528 bytes, the CS
must first be asserted then an
opcode 0BH must be clocked into the device followed by three address bytes and a dummy
byte. The first 13 bits (PA12 - PA0) of the 23-bit address sequence specify which page of the
main memory array to read, and the last 10 bits (BA9 - BA0) of the 23-bit address sequence
specify the starting byte address within the page. To perform a continuous read with the page
size set to 512 bytes, the opcode, 0BH, must be clocked into the device followed by three
address bytes (A21 - A0) and a dummy byte. Following the dummy byte, additional clock pulses
on the SCK pin will result in data being output on the SO (serial output) pin.
The CS pin must remain low during the loading of the opcode, the address bytes, and the read-
ing of data. When the end of a page in the main memory is reached during a Continuous Array
Read, the device will continue reading at the beginning of the next page with no delays incurred
during the page boundary crossover (the crossover from the end of one page to the beginning of
the next page). When the last bit in the main memory array has been read, the device will con-
tinue reading back at the beginning of the first page of memory. As with crossing over page
boundaries, no delays will be incurred when wrapping around from the end of the array to the
beginning of the array. A low-to-high transition on the CS pin will terminate the read operation
and tri-state the output pin (SO). The maximum SCK frequency allowable for the Continuous
Array Read is defined by the f
CAR1
specification. The Continuous Array Read bypasses both
data buffers and leaves the contents of the buffers unchanged.
6.3 Continuous Array Read (Low Frequency Mode: 03H): Up to 33 MHz
This command can be used with the serial interface to read the main memory array sequentially
without a dummy byte up to maximum frequencies specified by f
CAR2
. To perform a continuous
read array with the page size set to 528 bytes, the CS
must first be asserted then an opcode,
03H, must be clocked into the device followed by three address bytes (which comprise the 24-bit
page and byte address sequence). The first 13 bits (PA12 - PA0) of the 23-bit address sequence
specify which page of the main memory array to read, and the last 10 bits (BA9 - BA0) of the
23-bit address sequence specify the starting byte address within the page. To perform a contin-
uous read with the page size set to 512 bytes, the opcode, 03H, must be clocked into the device
followed by three address bytes (A21 - A0). Following the address bytes, additional clock pulses
on the SCK pin will result in data being output on the SO (serial output) pin.
The CS pin must remain low during the loading of the opcode, the address bytes, and the read-
ing of data. When the end of a page in the main memory is reached during a Continuous Array
Read, the device will continue reading at the beginning of the next page with no delays incurred
