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Question, i.MX25 unused pin handling

Question asked by AVNET JAPAN FAE (team share account) on Oct 6, 2016
Latest reply on Oct 11, 2016 by Yuri Muhin

Dear team,

 

I would like to ask about unused pin handling of i.MX25.

(1)

As for JTAG related pins of i.MX253, the following handling is done on my customer’s board. Are these correct when JTAG is not used?

- RTCK/TCK/TMS/TDI/TDO/TRSTB/DE_B : NC

- SJC_MOD : Pull-down through 10K ohm register.

TDO pad will be INPUT pad after reset, then it may need some external pull-up. Is it true?

(2)

As for USBPHY1 related pins of i.MX253, the following handling is done on my customer’s board. Are these correct when USBPHY1 is not used?

- USBPHY1_VBUS/USBPHY1_UID/USBPHY1_DP/USBPHY1_DM : NC

- USBPHY1_RREF : Pull-up through 10K ohm register

- USBPHY1_VDDA/USBPHY1_UPLLVDD/USBPHY1_VDDA_BIAS : connected to 3.3V

- USBPHY1_VSSA/USBPHY1_UPLLVSS/USBPHY1_VSSA_BIAS : Connected to GND

(3)

As for USBPHY2 related pins of i.MX253, the following handling is done on my customer’s board. Are these correct when USBPHY2 is not used?

- USBPHY2_DP/USBPHY2_DM : NC

- USBPHY2_VDD : Connected to 3.3V

- USBPHY2_VSS : Connected to GND

 

Thanks in advance.

Miyamoto

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