Skip to main content

Detecting #WP pin state on AT25FF321A and AT25SF321B


2 months ago

Posted by uzer 10 points 1 reply

For both the AT25FF321A and AT25SF321B that are configured for  hardware protection with the #WP pin (SRP1,0 = 01) what is the lowest impact way of detecting the state of the #WP pin (ability to write to status registers)?

As most of the R/W status register bits are related to configuring protection then if they are modified to test the ability to write the status registers then any change will need reverting afterwards, leading to a R,W,R,W sequence.



2 months ago

gordonmacnee 220 points

Hello Uzer,

Some of our older parts have a flag within the status reg to indicate the state of the /WP pin but the newer parts do not. The RWRW sequence is your best option but write to the VOLATILE registers only. This will be MUCH faster and will not impact the endurance - note also that the endurance of the non-volatile status registers is not guaranteed to be 100k but will typically be between 10k and 20k in most of our devices.