i.MX6ULL+SPI to UART CPU usage high

[m_c]

Customer use i.MX6ULL+SPI to UART (Pericom PI7C9X1170) and found CPU usage high.

Any experience use i.MX with SC16IS740/750/760?

[igorpadykov]

Hi m.c.

>Any experience use i.MX with SC16IS740/750/760?

this configuration was not used in official nxp bsps, so I am afraid there is no such 

experience. In general one can try to use ecspi with dma, add  "dmas" property

fsl-imx-cspi.txt\spi\bindings\devicetree\Documentation - linux-imx - i.MX Linux kernel 

or assign this task to M4 core using SDK:

• Windows Installer: MCUXpresso SDK2.2 for i.MX 6ULL

Best regards
igor
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[alif_chen]

>In general one can try to use ecspi with dma, add  "dmas" property

>fsl-imx-cspi.txt\spi\bindings\devicetree\Documentation - linux-imx - i.MX Linux kernel

The 'dmas' is enabled in imx6ull.dtsi. It doesn't help the issue. 

Best regards,
Alif

[igorpadykov]

use option with dedicated M4 core for spi task:

Windows Installer: MCUXpresso SDK2.2 for i.MX 6ULL

Best regards
igor

[alif_chen]

Hi igorpadykov,

i.MX6ULL doesn't have M4 core. Am I wrong?

Thank you

Best regards,
Alif

[igorpadykov]

Hi Alif

you are right, sorry.

Best regards
igor