S25FL256SDPNFVC datasheet(72/149 Pages) CYPRESS

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Document Number: 001-98283 Rev. *M

Page 71 of 148

S25FL128S/S25FL256S

9.1.9

Reserved

Some instructions are reserved for future use. In this generation of the S25FL128S and S25FL256S some of these command

instructions may be unused and not affect device operation, some may have undefined results.

Some commands are reserved to ensure that a legacy or alternate source device command is allowed without affect. This allows

legacy software to issue some commands that are not relevant for the current generation S25FL128S and S25FL256S devices with

the assurance these commands do not cause some unexpected action.

Some commands are reserved for use in special versions of the FL-S not addressed by this document or for a future generation.

This allows new host memory controller designs to plan the flexibility to issue these command instructions. The command format is

defined if known at the time this document revision is published.

9.2

Identification Commands

9.2.1

Read Identification - REMS (Read_ID or REMS 90h)

The READ_ID command identifies the Device Manufacturer ID and the Device ID. The command is also referred to as Read

Electronic Manufacturer and device Signature (REMS). READ-ID (REMS) is only supported for backward compatibility and should

not be used for new software designs. New software designs should instead make use of the RDID command.

The command is initiated by shifting on SI the instruction code “90h” followed by a 24-bit address of 00000h. Following this, the

Manufacturer ID and the Device ID are shifted out on SO starting at the falling edge of SCK after address. The Manufacturer ID and

the Device ID are always shifted out with the MSB first. If the 24-bit address is set to 000001h, then the Device ID is read out first

followed by the Manufacturer ID. The Manufacturer ID and Device ID output data toggles between address 000000H and 000001H

until terminated by a low to high transition on CS# input. The maximum clock frequency for the READ_ID command is

133 MHz.

Figure 44. READ_ID Command Sequence

Instruction

ADD (1)

SCK

High Impedance

MSB

90h

SCK

Manufacture ID

MSB

Device ID

MSB

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