6

AT25DF512C

DS-25DF512C–030A–4/2014

Figure 5-1.

SPI Mode 0 and 3

5.1

Dual Output Read

The ATx features a Dual-Output Read mode that allow two bits of data to be clocked out of the device every clock cycle

to improve throughput. To accomplish this, both the SI and SO pins are utilized as outputs for the transfer of data bytes.

With the Dual-Output Read Array command, the SI pin becomes an output along with the SO pin.

6.

Commands and Addressing

A valid instruction or operation must always be started by first asserting the CS pin. After the CS pin has been asserted,

the host controller must then clock out a valid 8-bit opcode on the SPI bus. Following the opcode, instruction dependent

information such as address and data bytes would then be clocked out by the host controller. All opcode, address, and

data bytes are transferred with the most-significant bit (MSB) first. An operation is ended by deasserting the CS pin.

Opcodes not supported by the AT25DF512C will be ignored by the device and no operation will be started. The device

will continue to ignore any data presented on the SI pin until the start of the next operation (CS pin being deasserted and

then reasserted). In addition, if the CS pin is deasserted before complete opcode and address information is sent to the

device, then no operation will be performed and the device will simply return to the idle state and wait for the next

operation.

Addressing of the device requires a total of three bytes of information to be sent, representing address bits A23-A0.

Since the upper address limit of the AT25DF512C memory array is 00FFFFh, address bits A23-A16 are always ignored

by the device.

SCK

CS

SI

SO

MSB

LSB

MSB

LSB

Table 6-1.

Command Listing

Command

Opcode

Clock

Frequency

Address

Bytes

Dummy

Bytes

Data

Bytes

Read Commands

Read Array

0Bh

0000 1011

Up to 85 MHz

3

1

1+

03h

0000 0011

3

0

1+

Dual Output Read

3Bh

0011 1011

Up to 50 MHz

3

1

1+

Program and Erase Commands

Page Erase

81h

1000 0001

Up to 85 MHz

3

0

0

Block Erase (4 Kbytes)

20h

0010 0000

Up to 85 MHz

3

0

0

Block Erase (32 Kbytes)

52h

0101 0010

Up to 85 MHz

3

0

0

D8h

1101 1000

Up to 85 MHz

3

0

0