KEAZN64 SPI CS Goes High inbetween packet

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KEAZN64 SPI CS Goes High inbetween packet

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e1ali
Contributor I

Hello,

I'm currently interfacing with a device over SPI using the KEAZN64 microcontroller. I'm using Processor Expert in KDS for development, since the later NXP tools do not support the KEA line of micros. The device I'm interfacing with can operate up to 3.6Mhz. I've currently set the clock speed to 500KHz and I can interface over SPI just fine. When I increase the speed to 1MHz I'm seeing a small pulse on the CS line that breaks the existing code. I've attached a picture of a correct packet @500KHz and an incorrect packet @ 1MHz.

500 KHz:

500KHz.png

1 MHz:

1MHz.png

As you can see in the 1MHz picture, the CS line goes high after the 4th byte for some reason, but this doesn't happen when I run it at 500KHz.

I'm using PE in KDS to generate the SPI code, and here is the diff between 500KHz and 1MHz:

500KHz:

/* SPI0_BR: ??=0,SPPR=0,SPR=4 */
SPI0_BR = (SPI_BR_SPPR(0x00) | SPI_BR_SPR(0x04)); /* Set baud rate register */

1MHz:

/* SPI0_BR: ??=0,SPPR=0,SPR=3 */
SPI0_BR = (SPI_BR_SPPR(0x00) | SPI_BR_SPR(0x03)); /* Set baud rate register */

I'd appreciate any help!

embeddedone.com
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CarlosGarabito
NXP TechSupport
NXP TechSupport

Sorry, we no longer support processor expert, neither KDS, we recommend you to switch to S32 Design Studio for Arm (https://www.nxp.com/design/software/development-software/s32-design-studio-ide/s32-design-studio-for...)

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