QSPI clock waveform

RE: QSPI clock waveform

Håkon Alseth — Fri, 29 Dec 2023 12:29:24 GMT

Happy new year to you as well!

Kind regards,

Håkon

RE: QSPI clock waveform

Poplar — Fri, 29 Dec 2023 10:25:36 GMT

[quote userid="2115" url="~/f/nordic-q-a/106913/qspi-clock-waveform/461906"]Can you share how the signal looks wrt. rising/falling edge?[/quote]

will show you next week, and

Happy New Year.

RE: QSPI clock waveform

Håkon Alseth — Thu, 28 Dec 2023 08:40:51 GMT

Hi,

[quote user="Poplar"]if we use the IOs which are not dedicated QSPI ports, is the easyDMA/DMA function also impacted?[/quote]

The module will work as intended on other pins. See here: https://devzone.nordicsemi.com/f/nordic-q-a/47151/qspi-pins-in-52840/186409#186409

[quote user="Poplar"]overall trace length is 8.8mm[/quote]

This should be short enough.

Can you share how the signal looks wrt. rising/falling edge?

Kind regards,

Håkon

RE: QSPI clock waveform

Poplar — Thu, 28 Dec 2023 02:52:48 GMT

Hi Håkon

SPI_CLK, p0.04

SPI_CS, p0.06

SPI_D0, p0.26

SPI_D1, p0.08

SPI_D2, p0.22

SPI_D3, p0.20

overall trace length is 8.8mm

if we use the IOs which are not dedicated QSPI ports, is the easyDMA/DMA function also impacted?

thanks

RE: QSPI clock waveform

Håkon Alseth — Wed, 27 Dec 2023 11:18:46 GMT

Hi,

Q1: Can you share how the signal looks?

Q2: How large is the trace from nRF to QSPI-flash?

P0.04 isn't limited in terms of switching frequency, but QSPI has dedicated recommended pins:

The overall capacitance, when you probe the pin, will also change. I would recommend that you use a low-capacitance probe to ensure less further loading of the signal.

Kind regards,

Håkon

RE: QSPI clock waveform

Poplar — Wed, 27 Dec 2023 11:02:32 GMT

Hi Håkon

the schematic is fixed now, we can't change to other pins, high drive mode is set already.

if we switch the p0.04 to 32MHz, not under QSPI but a simple IO, will the square wave still distort as a sine wave?

we didn't see p0.04 marked as some limitation as digital IO if take the reference from datasheet page 159. is there other information we shall take into consideration too? Or what is the difference between p0.04 and p0.19?

Thanks.

RE: QSPI clock waveform

Håkon Alseth — Wed, 27 Dec 2023 10:15:39 GMT

Hi,

You should use the dedicated QSPI pins for QSPI operation:

https://infocenter.nordicsemi.com/topic/ps_nrf52840/pin.html?cp=5_0_0_6_0

Please note that you must also configure H0H1 (high drive) on QSPI pins:

https://infocenter.nordicsemi.com/topic/ps_nrf52840/gpio.html?cp=5_0_0_5_8_1_9#register.PIN_CNF-0-31

Kind regards,

Håkon