Short frame mode of the PCM4204

user459077038

Other Parts Discussed in Thread: PCM4204, PCM4204EVM

Hi,

In the data sheet of PCM4204, "Figure 4. PCM Data Formats: Tim Division Multiplexed(TDM)". I cannot understand the data allocation in the short frame mode.It says that the short mode support 4 channels, or two PCM4204 devices.

1, Assume that fs=48kHz, BCK=128fs, there is only 1 PCM4204(4ch).

So, I got 128 bit (32bit * 4ch )（8 don't care bits per channel per sample） per sample. According to the datasheet, there are 8 slots per frame, frame length is 128 BCKs. How is the data allocated in these 8 slots?

2,The figure.4 says that short frame mode support 2 PCM4204 devices. but two PCM4204 is 8 channels , that is 32*4*2=256bit data, How is the data allocated in these 8 slots?

Thanks.

Regards,

Fantastone

over 8 years ago

0 Justin Bohr over 8 years ago

TI__Mastermind 27920 points

Hi Fantastone,

When in short frame it looks like if using 8 channels, it will output at 16 bits per channel, thus being 128 bits per frame.

Do you have an EVM to test this on?

Justin

0 user459077038 over 8 years ago in reply to Justin Bohr

Prodigy 210 points

Hi Justin,
Yes, I have purchased a PCM4204EVM board, sevral days ago. I have 3 questions:
1, According to the data sheet: if use short frame mode, the SUB pin will be ignored. So, if using 8 channels, which is 2 PCM4204 chips, how could it determine which chip's data goes first?
2, If I use single PCM4204 chip in short frame mode, will i get four 32-bit(8 don't care bits) data in one frame?
3, What should I do to test the data allocation in one frame?

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Short frame mode of the PCM4204