Inquiry about SPI of MPC5746C

[kimdukyu]

SPI1 of MPC5746C is used.

It communicates with Qualcomm AP (Master), and the frequency is 1MHz.

When communicating at 1 MHz, data is normally received.

(Yellow=CLK, Blue=MOSI, Red=MISO, Green=CS/SS)

However, when communicating with 5MHz, data cannot be received.

As shown in the picture above, the MISO(PH15 pin) line becomes HIGH.

We need 5Mhz communication.

How do I set the MCU SPI to communicate with 5MHz?

Please answer this question.

[PetrS · Accepted solution]

Hi,

seems the slave is not able to prepare data in time for this high rate. Not sure what driver you are using.
Try to assign highest interrupt priority for SPI module if interrupt is used or consider using DMA to handle slave response, if you know in advance how many bytes will be requested.

BR, Petr