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Linux/DS90UB941AS-Q1: On/Off test pattern will trigger INTB interrupt

enson Steven
Intellectual 630 points
Part Number: DS90UB941AS-Q1

Tool/software: Linux

I use a 941 chip ,and have some questions

1. when cpu have no mipi output, some of our board cannot communication with the remote chip with back channel. I2C & remote GPIO not work.(the ratio is 20%),when mipi output is ready, all of them can use back channel. so when cpu have no output I try to use internal clock and enable test pattern to use i2c to control the remote chip, It also work. so to use back channel, must have video data on fpd?

2.when I use internal clock on&off test pattern will trigger a  INTB interrupt(I set the 0xC6=0x41),but on UB947 on/off test pattern will not trigger HPD, they are different? to avoid this interrupt I try to set 0xC6 =0x00 when

I enable&disable test pattern,but the interrput still occur, It seems I can't mask it.why?

3, I set REM_INTB_CTRL 0x30 = 0x0A, but re_intb pin still have a falling edge when remote deserializer have interrupt, so the config means GPIO pins will mirror the re_intb pin, and re_intb still work?

4. in 2:2 mode, once one port have locked a link, then another port locked a link will not trigger a HPD interrupt. Can 941 to make port0/port1 HPD  independent?

Thanks.

B&R

Enson Liu

  • 0
    TI__Guru** 103215 points
    Hello Enson,

    We will look into this and get back to you on Monday.

    Best Regards,
    Casey
  • 0 in reply to Casey McCrea
    TI__Guru** 103215 points
    Hello Enson,

    For the first part of your question, can you please try setting DSI to non-continuous clock when the DSI input is not active? This seems to fix the issue on some devices when there is no DSI input allowing switch over to always on clock.

    I'm not sure exactly what the question is for number 3, and for number 4 I don't believe there is a way to make the HPD independent
  • 0 in reply to Casey McCrea
    Expert 1595 points

    Hello Casey,

    For this case , We are using 941 and 948 to transmit vedio to panel, and the panel is HV sync mode.My mipi output is vedio mode,RGB888,the display timing is config as the panel spec.

    But nothing show on the screen.I have another panel which used DE mode, and I can drive this panel display the right things. So I think I should config 941&948 to

    work on HV mode. I try to config the FRC_CONTROL 0x29【bit7】 = 1 , but panel still show nothing. How should I config the 941&948? Thanks！

  • 0 in reply to Casey McCrea
    Intellectual 630 points

    Hello Casey,

     Thank you for reply the question.

    1.I can try to non-continuous clock, but what do you mean by"fix the issue on some devices",you mean even use non-continuous clock, we still can't cover all for the 941 chips to use back channel with no viedo data?

    2.for number 2, can you tell me how to disable the interrput by 941 INTB pins?

    3 fro number 3,I just want to know is the gpio and remote_intb can output the remote interrupt simultaneously?

    Thank you!

  • 0 in reply to enson Steven
    TI__Guru** 103215 points

    Hello Enson,

    1. With no DSI input and no REFCLK applied to 941AS, in order to default reliably to the internal oscillator clock, the DSI mode must be set to non-continuous. This only applies to the situation where there is no video input or REFCLK applied 

    2. To disable the REM_INTB_CTRL, please write 0x30 = 0x00

    3. I am not sure I understand the question here. It would need more clarification

    Best Regards,

    Casey