UART port configuration

sanketparekh — Tue, 17 Apr 2018 14:16:52 GMT

Greetings,

I am using IMX6Q processor on my custom board.

I am trying to configure one of the UART port in LINUX kernel.

After configuration i am getting 2.8V on TX pin instead of 3.3V and 3.3V on RX pin.

I am using 3.3V on NVCC_EIM power domain for UART.

Firmware configuration:

UART_TX: SRE_FAST, DSE_DISABLE, SPEED_MED, CTL_HYS.

UART_RX: SRE_FAST, DSE_DISABLE, SPEED_MED, CTL_HYS, CTL_PUS_100K_UP, CTL_PKE, CTL_PUE.

Above configuration are used by kernel as a pad value of device tree node.

What could be the cause for this issue?

Thank you.

Sanket

Re: UART port configuration

igorpadykov — Tue, 17 Apr 2018 23:05:53 GMT

Hi Sanket

one can recheck pad power supplies using Table 100. 21 x 21 mm Functional Contact Assignments

"Power Group" i.MX6DQ Datasheet, in general UART can be muxed from pad with other power domain.

http://www.nxp.com/docs/en/data-sheet/IMX6DQCEC.pdf

check i.MX6 System Development User’s Guide for common power supply recommendations,

note all power supply should be applied even not used, exceptions are given in sect.2.8 Unused analog interfaces.

https://www.nxp.com/docs/en/user-guide/IMX6DQ6SDLHDG.pdf

Best regards
igor
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UART port configuration

Re: UART port configuration