1. Overview

This section describes the status register of the GD25LQ64 flash memory chip. The status register is a critical part of controlling and monitoring the memory's operation. It holds flags and configuration bits that affect how the memory responds to commands. You need to read and sometimes write to the status register to control the flash.

2. Key Status Register Bits (Table – Organized for Better Understanding)

Bit	Name	Description	Volatile/Non-Volatile	Read/Write	Notes
S15	SUS1	Suspend Programming/Erasing	Non-Volatile	Read	Related to power management (not elaborated here)
S14	CMP	Configuration Mode Protect	Non-Volatile	Read	Protects the configuration mode, preventing unauthorized changes
S13	LB3	Lock Bit 3	Non-Volatile	Read	Part of a series of lock bits for read protection (not fully explained)
S12	LB2	Lock Bit 2	Non-Volatile	Read	Part of a series of lock bits for read protection (not fully explained)
S11	LB1	Lock Bit 1	Non-Volatile	Read	Part of a series of lock bits for read protection (not fully explained)
S10	SUS2	Suspend Programming/Erasing	Non-Volatile	Read	Related to power management (not elaborated here)
S9	QE	Quad Enable	Non-Volatile	Read	Enables Quad SPI mode
S8	SRP1	Status Register Protect 1	Non-Volatile	Read/Write	Controls how the status register can be modified
S7	SRP0	Status Register Protect 0	Non-Volatile	Read/Write	Controls how the status register can be modified
S6	BP4	Block Protect 4	Non-Volatile	Read/Write	Part of block protection scheme
S5	BP3	Block Protect 3	Non-Volatile	Read/Write	Part of block protection scheme
S4	BP2	Block Protect 2	Non-Volatile	Read/Write	Part of block protection scheme
S3	BP1	Block Protect 1	Non-Volatile	Read/Write	Part of block protection scheme
S2	BP0	Block Protect 0	Non-Volatile	Read/Write	Part of block protection scheme
S1	WEL	Write Enable Latch	Volatile	Read/Write	Must be set to '1' to allow writing to the status register or memory. Cleared on power loss.
S0	WIP	Write In Progress	Volatile	Read	Indicates whether the memory is busy with an operation.

3. Detailed Explanations of Key Bits

️· WIP (Write In Progress): This is *crucial*. You *must* check this bit before attempting to write to the status register or perform programming/erasing operations. If WIP = 1, the memory is busy, and another write attempt will likely fail or cause data corruption.

️· WEL (Write Enable Latch): This acts as a gatekeeper. You *must* set WEL to '1' before you can write to the status register or program/erase memory. WEL is cleared upon power loss, so you have to re-enable writes after power cycling.

️· BPx (Block Protect): These bits define software protection areas. When set, they prevent programming and erasing of specific memory blocks. This is used for write protection of critical data areas. The size of the protected area depends on the values of these bits (refer to Table 1 in the datasheet).

️· SRPx (Status Register Protect): This is vital for securing the status register itself. These bits control how the status register can be modified. There are several protection modes:

- Software Protection: (Default) Status register can be written to after a Write Enable command.
- Hardware Protection: Status register is locked and cannot be written to, dependent on WP# pin state.
- Power Supply Lock-Down: Status register is permanently protected until the next power cycle.
- One-Time Programmable (OTP) Protection: Status register is permanently protected and cannot be written to. *(Special order)*

4. Important Considerations

️· Volatility: Understand which bits are volatile (lose their value when power is removed) and which are non-volatile (retain their values even without power).
️· Sequence of Operations: Always follow the sequence of operations as defined in the datasheet. This typically involves:
1. Sending a Write Enable command (setting WEL).
2. Reading the WIP bit to ensure the memory is not busy.
3. Writing to the status register (if needed).
4. Reading the WIP bit again to ensure the write operation is complete.

In summary, this excerpt describes how to control and protect the flash memory using its status register. Careful attention to the meanings of the status register bits and the correct sequence of operations is essential for reliable operation.