CY15B108QI enter hibernate Mode

Nelson · ‎Oct 20, 2021

The MCU I use is stm32L476RG.

The test steps are as follows:

1. Put FRAM into hibernation mode,

2. Read the FRAM status register and read the value 0x00, indicating that FRAM has entered the hibernate state.

3. Put the MCU into hibernation mode,

4. Wake up MCU after 1 second,

4. Read the FRAM status register, and read the return value 0x40.

The problem is that I shouldn't be able to read the FRAM data at this point because it's still in hibernation mode and I haven't woken it up. I did not find that the CS PIN was pulled down for more than 4.5ms through the logic analyzer.

Nelson · ‎Oct 22, 2021

Thank you for your help. After testing, I now understand that CS Line does not need to be pulled down for more than 4.5ms, but just give it a falling edge and then you can pull it up. I think the instructions in the data sheet for exiting hibernation mode are not very clear and can be confusing. Thank you again .

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CY15B108QI enter hibernate Mode

CY15B108QI enter hibernate Mode

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