Which registers need to be changed for proper XBAR routing?

[nicholasc]

I am trying to route quadrature decoder signals through the crossbar switches. I'm having trouble figuring out what exactly I need to change because the documentation is scattered throughout IOMUX/ XBAR/ ENC and other chapters of the reference manual.

Currently I am trying to route GPIO_SD_B0_03 to ENC1_HOME. I won't be able to test until I get some boards back, but these are the steps I have gathered I need to make to route the signals:

1) Set SW_MUX_CTL_PAD_GPIO_SD_B0_03 to ALT_3. (Route pad to XBAR_INOUT07)

2) Set XBAR_INOUT07_SELECT_INPUT to 1. (Select SD_B0_03 as input instead of EMC_05)

3) Set IOMUXC_GPR_GPR6 so that XBAR_INOUT07 is set to input.

4) Finally, set the SEL69 field of XBARA1_SEL34 to 7. (Select XBAR_INOUT07 as XBAR1_OUT69)

Can someone confirm if this is correct? Also, do I need to make any changes to SW_PAD_CTL_PAD_GPIO_SD_B0_03?

Thanks,

Nicholas

[jorge_a_vazquez]

Hi Nicholas Chin

Yes, everything seems to be correct, please remember that SEL69 are the higher bits of XBARA1_SEL34. If you download the SDK of the RT1064, you will find two examples codes for the ENC module, where the API sets all of this.

Also, do I need to make any changes to SW_PAD_CTL_PAD_GPIO_SD_B0_03?

It depends on the hardware that you have, in the SDK examples that we provide don't set any pull resistor or anything special to the pin.

/* Slew Rate Field: Slow Slew Rate

Drive Strength Field: R0/6

Speed Field: medium(100MHz)
Open Drain Enable Field: Open Drain Disabled
Pull / Keep Enable Field: Pull/Keeper Enabled
Pull / Keep Select Field: Keeper
Pull Up / Down Config. Field: 100K Ohm Pull Down
Hyst. Enable Field: Hysteresis Disabled */

Hope this helps
Have a great day,
TIC

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