PCM1864 Energysense Signal Loss timeout register malfunction?

Troels Brondbjerg

Other Parts Discussed in Thread: PCM1864, PCM1865

I'm working with the PCM1864 using the Energysense function to power on/off my application. Signal sense in sleep mode works fine for the power on function. Signal loss in active mode is problematic due to issues with the signal loss timeout. The signal loss function works in general fine i just can't adjust the timeout in the timeout register.

When writing register 52 (0x34) for signal loss time I get strange behavior. According to the datasheet the register should take a value between 1 and 30 for timeout in minuttes. When writing values 0x05, 0x06, 0x07, 0x0D, 0x0E, 0x0F, 0x15, 0x16, 0x17, 0x1D, 0x1E, 0x1F the energy sense function stops working both in idle and active mode, when writing other values Energysense works fine but i can not change the timeout value the time out is depending on value between 30 and 90 sec.

Is this a known issue or have others experienced the same?

I have tested with both the PCM1864 in my application and the PCM1865 on the EVM module with the same results.

Regards

Troels

over 9 years ago

0 Justin Bohr over 9 years ago

TI__Mastermind 28020 points

Hi Torels,

This is a mistake in the data sheet, and we are working on a revision of the data sheet now. The SIG_LOSS_TIME register is actually register 0x33. Try writing to this register instead.

Justin

0 Troels Brondbjerg over 9 years ago in reply to Justin Bohr

Prodigy 50 points

Hi Justin

Thank you for your feedback.

I have used register 0x33 which seems to work ok - I can now adjust the timeout.

The timeout however is not very precise in my opinion. How precise should I expect the PCM186x can handle the timeout?

Kind regards

Troels

0 Justin Bohr over 9 years ago in reply to Troels Brondbjerg

TI__Mastermind 28020 points

Hi Troels,

The timeout is just using a counter and the clocks provided, so it should be reasonably precise, how far off are you observing the count?

Justin

0 Troels Brondbjerg over 9 years ago in reply to Justin Bohr

Prodigy 50 points

Hi Justin

Using values 1, 2, 3, 4 gives the right time in minutes, using values between 5 and 20 gives the time in half minutes (so to have a timeout of 10 minutes we write the value of 20).

Above this we have only tried with a value of 40 which never creates a timeout, but according to the datasheet the value should be 1-30 so that would be expected.

Have others seen similar behaviour?

Kind regards

Troels

0 Justin Bohr over 9 years ago in reply to Troels Brondbjerg

TI__Mastermind 28020 points

Hi Troels,

So i was testing these signal loss times, and noticed in your description you sat register 52 (0x34), the signal loss time register is actually register 0x33.

I tested at both 48 kHz and 96 kHz, 1, 2, 5,6 10, and 15 min signal loss times. All of them were within seconds of the correct time(probably due to my imperfect testing).

Justin

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PCM1864 Energysense Signal Loss timeout register malfunction?