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Original question:

TDA4VEN-Q1: How to enable TDA4Ventry WKUP_LFOSC0_XI/XO connected 32.768KHz crystal.

AM67: What to turn on WKUP_LFOSCO_XI/XO on AM67x

Rich Chen
Expert 4170 points
Part Number: AM67

Tool/software:

Champ, 

Following by the below e2e post, 

 TDA4VEN-Q1: How to enable TDA4Ventry WKUP_LFOSC0_XI/XO connected 32.768KHz crystal. 

I tried to read out 0x04508038 on AM67x EVM with SDK 10 .wic image and the value is 0x0 which means bit 7 is 0x0.

However, WKUP_LFOSX_XI/XO has clock output at all. 

I tried to modify this bit to 0x1 and switch back to 0x0 again but found no response at all. 

Is there other register need to be set?

BR, Rich 

  • 0
    TI__Mastermind 19750 points

    Hi Rich,

    I have assigned your thread to the expert engineer who will be able to resolve this. Thank you for your patience.

    Thanks,

    Neehar

  • 0 in reply to Neehar Sawant
    TI__Mastermind 20080 points

    Rich,

    Let's break this problem into hardware and software. OK?

    Software:
    I guess I am a little concerned that 0x00 might not be the real value of the register.

    0450 803Ch MCU_CTRL_MMR_CFG0_LFXOSC_TRIM is supposed to have a value like 0x0012_1203
    of course, 
    0450 8038h MCU_CTRL_MMR_CFG0 MCU_CTRL_MMR_CFG0_LFXOSC_CTRL should expect a default of 0x80.
    Maybe the wic modified this value for you.... 

    In order to write to these registers, you need to write the proper values to the lock registers:
    0450 9008h MCU_CTRL_MMR_CFG0 MCU_CTRL_MMR_CFG0_LOCK2_KICK0
    0450 900Ch MCU_CTRL_MMR_CFG0 MCU_CTRL_MMR_CFG0_LOCK2_KICK1

    I suppose that you write (1 << 7) so that you were in effect resetting the register to its default state. Did you happen to read the register back? Were you able to change the register from 0x00 to 0x80?  (Or maybe my question should be: can you change the register value from 0x00 to 0x80 (and eventually back to 0x00)?)

    Hardware:
    What does the hardware look like?
    On the EVM, there is a 1 Megohm resistor that I think is killing the behavior. Could you remove this resistor (R207) and try again?

    Kevin

  • 0 in reply to Kevin Lavery
    TI__Expert 4170 points

    Kevin, 

    Thanks for the inputs.

    You are right on the shunt resister.   

    After removing the shunt resister 1M ohm R (R207) on EVM, I can see the 32.768K waveform even the amplitude is only 200mV. 

    I have confirmed the register value of 

    0x04508038 is 0x0

    0x0450803C is 0x0012 1203 

    as you described.

    Setting 0x04508038 to 0x80 can actually disable 32.768K output and set to 0x0 can enable it. 

    I change the value in 0x0450803C and found the amplitude will be changed accordingly. 

    This answer my question and ticket can be closed. Thank you!  

    BR, Rich