AT25QL128A datasheet(34/84 Pages) DIALOG

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AT25QL128A

DS-AT25QL128A–129E–01-2021

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 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-byte) of data without issuing multiple read instructions.

(See Section 8.31, 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 Read Parameter Bits P [4] and P [5] setting, the

number of dummy clocks can be configured as either 4 or 6 or 8. The default number of dummy clocks upon

power up or after a Reset (99h) instruction is 4.

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. (See Section 8.32 Burst Read with Wrap).

Figure 8-20. Fast Read Quad I/O Instruction (Initial instruction or previous M7-0 ≠ Axh, QPI mode, 80 MHz)

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