Quad-Serial Configuration (EPCQ) Devices Datasheet

ID 683078
Date 1/23/2020
Document Table of Contents

1.7.14. Erase Subsector Operation

The erase subsector operation allows you to erase a certain subsector in the EPCQ device by setting all the bits inside the subsector to 1 or 0xFF. This operation is useful if you want to access the unused subsectors as a general purpose memory in your applications. You must execute the write enable operation before the erase subsector operation.

When you execute the erase subsector operation, you must first shift in the erase subsector operation code, followed by the 3-byte addressing mode (A[23..0]) or the 4-byte addressing mode (A[31..0]) of the chosen subsector on the DATA0 pin. The 3-byte addressing mode or the 4-byte addressing mode for the erase subsector operation can be any address inside the specified subsector. For details about the subsector address range, refer to the related information below. Drive the nCS signal high after the eighth bit of the erase subsector operation code has been latched in.

Figure 21. Erase Subsector Operation Timing DiagramTo access the entire EPCQ256 or EPCQ512/A memory, use 4-byte addressing mode. In the 4-byte addressing mode, the address width is 32-bit address.

The device initiates a self-timed erase subsector cycle immediately after the nCS signal is driven high. For details about the self-timed erase subsector cycle time, refer to related the information below. You must account for this amount of delay before another page of memory is written. Alternatively, you can check the write in progress bit in the status register by executing the read status operation while the self-timed erase cycle is in progress. The write in progress bit is set to 1 during the self-timed erase cycle and 0 when it is complete. The write enable latch bit in the status register is set to 0 before the self-timed erase cycle is complete.