How does Deep Power-Down Work with QSPI and some example code.

[Cheets]

QSPI_Test.ino

Hi,

Just wondered about the following ....

Strange parts of this code ... Or things I don't understand

After the first READ in Setup() it successfully reads the data (Returns 0 = NRFX_SUCCESS), but the status flag
has the top 8 bits set to 0xFF which causes nrfx_qspi_mem_busy_check() to show 17 (Returns 17 = NRFX_ERROR_BUSY).
However masking the STATUS register with 8 reveals the Ready Status = 1, QSPI is ready!
This was why I wrote the QSPI_IsReady().

nrf_qspi_phy_conf_t not visible as a structure if you try and set it like this

    QSPIConfig.phy_if {
        .xxx = yyy,
        .aaa = bbb
     };
 
I don't know what the significance of the 48ms Deep Power-down Mode (DPM) is.
Will it go into DPM if not used for 48ms and then take 48ms to wake up if instructed?

Thanks

Paul

[Vidar Berg]

Hi,

I did not find any instructions on how to use the QSPI flash on this board, have you? I only found the datasheet for the flash IC: https://files.seeedstudio.com/wiki/github_weiruanexample/Flash_P25Q16H-UXH-IR_Datasheet.pdf

However masking the STATUS register with 8 reveals the Ready Status = 1, QSPI is ready

This means the QSPI peripheral itself is ready, but it does not say if the ext. flash IC is ready. For that you have to look at the SREG field in the STATUS register. What is the status value when it is read by the nrfx_qspi_mem_busy_check() function?

I don't know what the significance of the 48ms Deep Power-down Mode (DPM) is.
Will it go into DPM if not used for 48ms and then take 48ms to wake up if instructed?

I believe this is answered in the Deep power-down mode section of the QSPI chapter. The power down and wake up time must correspond with the timing spec. of the flash IC you use (see 10.30 Deep Power-down (DP) and the
5.3 AC Characteristics table in the P25Q16H datasheet).

Best regards,

Vidar