Hi
we configured a QSPI application on nRF52840.
its clock was assigned on p0.04/J1 in hardware design, now we notice that its waveform is close to a square wave as 30MHz maximum, but changes to similar as a sine wave if it is set to 32MHz.
does this mean p0.04 can't be run as such high frequency usage? or only the recommended usage is allowed for QSPI application?
Thanks
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.
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.
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
