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

I'm sorry about the late reply, but we're currently working through our backlog after the holiday season. Happy new year!

Indeed, a custom instruction is just that, custom. So you're able to modify most of it to do what you'd like, but doing so you should follow the OP code specified in the QSPI device you're using to make it do what you'd like. The custom instruction will be output from the nRF52840 to the external device, but the OP code and instruction you send can "tell" the external device to send data back if that's what you want.

Please note that the nrfx_qspi_write() function is not a custom instruction, but a fixed function in our QSPI driver.

Best regards,

Simon

[wiz_yoo]

Hi, Simon.

Thank you for answer.

The 'nrfx_qspi_write()' is a fixed function, so WREN and RDSR are not a controllable item like the 'custom instruction'.

Is it right?

Best regards,

Yoo

[Simonr]

Hi

You can make a custom instruction that uses the OP code for WREN and RDSR as well. The OP code for every instruction should be in the datasheet of the external flash you're using.

Best regards,

Simon

[wiz_yoo]

Hi, Simon.

I'm sorry for unclear question.

I want to use "nrfx_qspi_write" function for write to the Graphics RAM.

According to "nRF52840 PS", there are no signals (RDSR and WREN).

But,  the waveform shows RDSR and WREN singal.

Could I prevent signals (RDSR & WREN), when using "nrfx_qspi_write". 

Best regards,

Yoo