About QSPI opcode (WREN ) for Instruction Set

[wiz_yoo]

Hello.

I have question for QSPI OPCODE.

According to "nRF52840_PS_V1.5", WREN optional at "the custom Instruction".

- using function: nrf_drv_qspi_cinstr_xfer

Is it the same for "the Instruction set "?

Is it possible to set the signal not to be output? (i.e. WREN, RDSR)

- using function: nrfx_qspi_write (i.e. PP, PP4O)

Thank you.

[Simonr]

Hi

What lines are your waveform from? To me it seems like Line 1 is the IO0 and line 2 is the SCK, is that correct? If so, I don't see what the issue is? Do you not want the RDSR and WREN signals to be called at all? If so, you won't be able to do page programming, asyou need to read the status register (RDSR) and enable writes (WREN) before you'll be able and allowed to program a page on the external device.

Best regards,

Simon

[wiz_yoo]

Hi, Simon

I am sorry about late response.

Yes, Line 1 is IO0 and Line 2 is SCK.

We will change interface QSPI to SPI for LCD Driver.
Because we use external flash with QSPI and it needs WREN and RDSR signals as you mentioned.

But, my question is for the following reasons.

1. QSPI is intended to update data to Graphics RAM of LCD Module, not the FLASH.
2. When using the SPI interface, the GRAM update is normal without WREN and RDSR signals.
- The LCD module supports both QSPI and SPI.
3. There is not any requirement WREN and RDSR at LCD Module datasheet.

Best regards,

Yoo