topic Re: ECSPI chip select and boot from SPI-Flash in i.MX Processors

ECSPI chip select and boot from SPI-Flash

宗標廖 — Fri, 03 Jul 2015 01:42:19 GMT

Hello, Community

I came to a problem when I want to boot from SPI-FLash,

Please refer the attachment for details.

Best Regards,

ZongbiaoLiao

igorpadykov — Fri, 03 Jul 2015 03:01:18 GMT

Hi 宗標廖

V20 gpio1.31 can be used by linux and mfg tools as ENET_MDC signal.

Also gpio1.31 has NVCC_ENET power domain,

while pad U6 - NVCC_GPIO, G21 -NVCC_EIM0.

Probably ADC has incompatible voltage levels used by these i.MX6 pads.

In general one can use a GPIO as chip select for SPI slave.

You can check if ADC is fully powered when i.MX6 begin to boot from SPI and

that ADC should no be powered before i.MX6.

Best regards

igor

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宗標廖 — Fri, 03 Jul 2015 09:49:03 GMT

Hello,Igor

According to the schematics of imx6q-sabreai cpu board, NVCC_ENET,

NVCC_GPIO and NVCC_EIM0 have the same properties,so the power

behavior of U6 and V20 shoud be the same also, is it right?

In case 2(please refer the previous attachment), after I powed on the board,

V20 pin is always on 3.3V voltage,this shoud disable the SPI slave A,so SPI

slave A should have no influence to SPI-FLASH when boot up, is it right?

igorpadykov — Fri, 03 Jul 2015 11:16:43 GMT

Hi ZongbiaoLiao

I think you should concentrate your attention on "SPI-A" chip,

because it can interfere with i.MX6.

How it is powered ? Is it powered before i.MX6 ?

It should be powered after all i.MX6 power supplies become stable.

Regarding V20 - just for test, suggest to disconnect it from i.MX6 and

connect permanently to 3.3V (inactive) level.

~igor