AT45DB321D datasheet(6/57 Pages) ATMEL

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3597N–DFLASH–04/09

AT45DB321D

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 fCAR1 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 fCAR1. 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 fCAR1 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 fCAR2. 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

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