Getting started with TAS5717

Michael Martin84

Other Parts Discussed in Thread: TAS5717

Hey guys,
I have some trouble getting the TAS5717 running:

The input signal is a 16 Bit-I2S, 44.1kHz, a simple 440Hz sine.

The first question, are these the minimal settings and right order to possibly get a sound output?

                OSCILLATOR TRIM REGISTER (0x1B) -> 0x00
                Reset
                SERIAL DATA INTERFACE REGISTER (0x04) -> 0x03 (I2S - 16 Bit)
                SYSTEM CONTROL REGISTER 2 (0x05) -> 0x00
                VOLUME REGISTERS (0x07) -> 0x00C0/ 0x00F0

If unmuting and independent from the input signal, there is a sine-shaped output with about 300kHz (+-0.5V) and a lot of peaks, where does that come from?

There is also another issue on the addressing, trying to address the tas5717 with (0101 010) 0x54, it won't work, but if sending the right shift, (0010 101) 0x2A it works as wanted.

Now strangely: writing a value to a register on the chip with address 0x2A and read it afterwards, it is written value, not shifted. And ideas about that?

Thanks in advance!
Michael

over 9 years ago

0 Don Dapkus over 9 years ago

TI__Guru**** 189399 points

Hi, Michael,

Welcome to e2e, and thanks for your interest in our products.

Are you using our EVM and GUI? If so, this app note might help clarify things.

-d2

0 Michael Martin84 over 9 years ago in reply to Don Dapkus

Prodigy 30 points

Hi Don,

no we are not.
We controll the TAS with an unix environment, where we got some simple hacks for the communication.

Best regards

Michael

0 Diego Melendez over 9 years ago in reply to Michael Martin84

TI__Guru 57800 points

Hello Michael,

On the start-up sequence, when you apply reset, all the registers return to their default value. So you need to write OSCILLATOR TRIM REGISTER (0x1B) with 0x00 after reset.

On the I2C address issue, can you please be more specific about the I2C sequence you are using?.

For I2C communications, a 0 is needed to start before introducing the address.

Also there could be a misunderstanding with the R/W bit. You can refer to this Wiki page for a better explanation of this:

I2C address clarification

Best Regards,

-Diego Meléndez López
Audio Applications Engineer

0 Michael Martin84 over 9 years ago in reply to Diego Melendez

Prodigy 30 points

Hi Diego,

thanks a lot, so i was wrong, twice(or more)..

The minimal startup should be fine then. (:

As we are using the standard linux i2c driver we only pass the 7 bit address, 0x2a, this then gets append with the W/R Bit, which makes it 0x56, yeah..

May the frequency around 300 kHz come from the PWM carrier?

Best regards,

Michael

0 Diego Melendez over 9 years ago in reply to Michael Martin84

TI__Guru 57800 points

Hi Michael,

As you say, the start-up is fine, also, the output signal with a 300-KHz frequency is the remnant part of the PWM signal carrier that passed through the output filter.

Best Regards,

-Diego Meléndez López
Audio Applications Engineer

Audio

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Getting started with TAS5717