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TPS65217C bringup problem

Rajput Ajay
Intellectual 310 points
Other Parts Discussed in Thread: AM3354

Dear Sir,

We are using tps65217C PMIC for powering AM3354 processor. i have connected 5v input to pmic AC input and trying to check the SYS voltage output. We have capacitor of 22uF connected on SYS pin. But i am not getting 5v on SYS pin of pmic chip.  

Battery is not connected to BAT and BAT1 terminals of chip.  TS pin is also floating. I want to know that if battery is not connected and if we give 5v to AC input, can we have 5v on SYS pin. 

Is any configuration required to pmic by I2c for this purpose or by default, we can check voltage on SYS output just by applying 5v on AC input pin.

  • 0
    TI__Expert 4525 points

    In order to detect AC insertion there has to be a rising edge on the AC pin.  This edge must take less than 50ms.  Can you verify that the edge is less than 50ms?  Can you also verify that you do not hit the OVP threshold for AC pin?  OVP threshold is ~6V.

    If neither of those suggestions work, please try to press the push-buttton (or simulate a press by putting a falling edge and subsequent rising edge on the PB pin). 

     

    There is no need for I2C action to get AC detected.  Just need AC greater than 4.3V and less than 5.8V 

  • 0 in reply to Stephen Nortman
    Intellectual 310 points

    Hi Stephen,

    Thanks for reply.

    I have checked the AC pin supply rising edge which was less than 50ms. Problem is solved and i was able to check the 5v on SYS pin.

    Problem was that there was SYS (5v) track going directly to MUX_IN without any voltage divider pin of PMIC due to which at start up PMIC was damaged. After removing this connection and replacing PMIC, the issue was resolved.

    Now we have AM335x processor out of reset mode.  I have referrred AM335x board bring up tips available on wikipedia.

    But another problem is that AM335x is sending 'C' character at 115200 bps on UART0 which is ok. But, hyperterminal is detecting inverting T whose ascii value is 0xC1. 

    The PC hyperterminal settings are 115200bps, 8 data bits, None Parity.

    I traced the data on CRO and found that the time taken by 1 bit is 7 us which should be ideally 8.2 to 8.6us according to 115200 baudrate.

    The crystal for AM3354 is of 24Mhz. I have checked that 24Mhz and it is coming on XTALIN and XTALout pin. Also, CLKOUT1 is showing 24Mhz.

    IF we are able to get 'C' on hyperterminal, then we are through for next level board bringup part.

    Please advice on same.

  • 0 in reply to Rajput Ajay
    TI__Expert 4525 points

    Rajput,

    I work with the power management and can answer questions related to that.  But for questions about the processor, you will need to refer to the AM335x forum.

    Regards,

    Stephen