I tried to set the SPI CLK to 20MHz at VDD=1.8V, but there was no output signal at PB13. When I change to 5 MHz it returns to normal, but the waveform seems to have been filtered by the low-pass filter. Finally, I set it to 2.5MHz to make it work stable. However, the patterns between PG11(C2) and PB13(C1) at the same frequency are different.
I want to confirm. Is that issue because the layout routing distance different between these two pins on the board? If I directly probe the IC pin, the pattern will be the same, right?
Hi @Foued_KH
Thank you for your explanation.
Now, I use the SPI6 instead of the SPI2, but a similar issue happening on the MOSI pin. When I use the PA7 as the MOSI, the signal amplitude can not reach 1.8V and occur unpredictable noise. But when I change top the PB5, the amplitude returns to normal level and the signal is stable. Is there a difference between these two pins?
Please refer to the pic below and the video in the attachment. The C1 is PA7 and C2 is PB5, the trigger level are all set to 500 mv.
These two pins setups are the same as below. And all enable the HSLV.
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_PULLDOWN;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF8_SPI6;
I'm worry that have another issue like this. If so, it means I can't set the same function on a different pin. Because the result may not be equal and will waste time to debug it.
