VS1053B as slave processor, slow playback in 16 bits PCM WAV @ 44100Hz

Designing hardware that uses VLSI Solution's devices as slave codecs such as an external MP3 decoder chip for a host microcontroller.
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rbodoira
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Joined: Sun 2018-03-25 20:38

VS1053B as slave processor, slow playback in 16 bits PCM WAV @ 44100Hz

Post by rbodoira » Sun 2018-03-25 20:44

Good afternoon, I write to make a query about your VS1053B codec. I am currently using this chip codec in my final thesis project of electronic engineering degree. The intention is to use the VS1053B to acquire uncompressed PCM WAV audio at 44100Hz (CD audio quality). The chip is used as a slave coprocessor, along with a Raspberry Pi3 (host processor). While I have performed tests reproducing and recording in mp3 and Ogg formats successfully, I have not been able to play or record in PCM WAV stereo 16bits at 44100Hz, the playback is slow and with samples lost, as if there was a problem of transfer speed in the SDI interface, I have verified the SPI clock of the Raspberry Pi3, and it can operate up to 32MHz. I understand that the SDI interface can work until CLKI / 4, XTALI is 12.288MHz, I have configured SCI_CLOCKF for maximum performance (SC_MULT x5.0), but I have not noticed any change. There is some special consideration for configuring the SPI clock in the VS1053B, which should be taken into account. I have based on the example "Microcontroller Playback and Recording Example using VS1053". Any contribution is welcome, thank you very much.

Greet attentively. Bodoira Raúl.

rbodoira
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Posts: 2
Joined: Sun 2018-03-25 20:38

VS1053B as slave processor, slow playback in 16 bits PCM WAV @ 44100Hz

Post by rbodoira » Sun 2018-03-25 20:48

Good afternoon, I write to make a query about your VS1053B codec. I am currently using this chip codec in my final thesis project of electronic engineering degree. The intention is to use the VS1053B to acquire uncompressed PCM WAV audio at 44100Hz (CD audio quality). The chip is used as a slave coprocessor, along with a Raspberry Pi3 (host processor). While I have performed tests reproducing and recording in mp3 and Ogg formats successfully, I have not been able to play or record in PCM WAV stereo 16bits at 44100Hz, the playback is slow and with samples lost, as if there was a problem of transfer speed in the SDI interface, I have verified the SPI clock of the Raspberry Pi3, and it can operate up to 32MHz. I understand that the SDI interface can work until CLKI / 4, XTALI is 12.288MHz, I have configured SCI_CLOCKF for maximum performance (SC_MULT x5.0), but I have not noticed any change. There is some special consideration for configuring the SPI clock in the VS1053B, which should be taken into account. I have based on the example "Microcontroller Playback and Recording Example using VS1053". Any contribution is welcome, thank you very much.

Greet attentively. Bodoira Raúl.

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Panu
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Re: VS1053B as slave processor, slow playback in 16 bits PCM WAV @ 44100Hz

Post by Panu » Mon 2018-03-26 8:09

Dear Sir,

Please read the [MCU Howto] checklist, there is a link below.

Where do you get the sound that is played? How fast can you read a block of data? How often does your process run in the Raspberry Pi? How are you handling the DREQ signal?

Please capture some of the data traffic with an oscilloscope in different time settings: 100ns/div, 10us/div, 1ms/div, 100ms/div so that we can get an idea of the general timing situation in your card.

-Panu
Info: Line In and Line Out, VS1000 User interface, Overlay howto, Latest VSIDE, MCU Howto, Youtube
Panu-Kristian Poiksalo, VLSI Solution Oy

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