AT25QL641 datasheet(30/77 Pages) DIALOG

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AT25QL641

DS-25QL641–130E–10/2018

Figure 7-19. Fast Read Quad I/O Instruction (previous M7-0 = Axh, SPI mode)

Wrap Around in SPI mode

The Fast Read Quad I/O instruction can also be used to access specific portion within a page by issuing a ‘Set Burst

with Wrap’ (77h) instruction prior to a ‘Fast Read Quad I/O’ (EBh) instruction. The ‘Set Burst with Wrap’ (77h)

instruction can either enable or disable the “Wrap Around” feature for the following ‘Fast Read Quad I/O’ instruction.

When “Wrap Around” is enabled, the data being accessed can be limited to an 8/16/32/64-byte section of a 256-byte

page. The output data starts at the initial address specified in the instruction, once it reaches the ending boundary of the

8/16/32/64-byte section, the output wraps around to the beginning boundary automatically until CS is pulled high to

terminate the instruction.

The Burst with Wrap feature allows applications that use cache to quickly fetch a critical address and then fill the

cache afterwards within a fixed length (8/16/32/64 bytes) of data without issuing multiple read instructions. (Please

refer to Section 7.32 Set Burst with Wrap).

Fast Read Quad I/O in QPI mode

When QPI mode in enabled, the number of dummy clocks is configured by the ‘Set Read Parameters’ (C0h) instruction

to accommodate a wide range applications with different needs for either maximum Fast Read frequency or minimum

data access latency. Depending on the state of read parameter bits P[4] and P[5], the number of dummy clocks can be

configured as either 4, 6, or 8. The default number of dummy clocks upon power up or after a Reset (99h) instruction is

The “Continuous Read Mode” feature is also available in QPI mode for Fast Read Quad I/O instruction. In QPI mode, the

“Continuous Read Mode” bits M7-0 are also considered as dummy clocks. In the default setting, the data output follows

the Continuous Read Mode bits immediately.

The “Wrap Around” feature is not available in QPI mode for Fast Read Quad I/O instruction. To perform a read operation

with fixed data length wrap around in QPI mode, a ‘Burst Read with Wrap’ (0Ch) instruction must be used. For more

information, refer to Section 7.33, Burst Read with Wrap (0Ch).

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