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Wi-Fi Bluetooth for Linux

Anonymous
Not applicable

Hi,

The defaule value of PCM clock is 512KHz, but we want to set 128KHz, so I config cyw43438 as follows:

1, Write_I2SPCM_Interface_Param

[MiniBoard]# hcitool cmd 0x3f 0x6D 0x01 0x01 0x00 0x00

< HCI Command: ogf 0x3f, ocf 0x006d, plen 4

  01 01 00 00

> HCI Event: 0x0e plen 4

  01 6D FC 00

2, Write_SCO_PCM_Int_Param

[MiniBoard]# hcitool cmd 0x3f 0x1C 0x00 0x00 0x00 0x01 0x01

< HCI Command: ogf 0x3f, ocf 0x001c, plen 5

  00 00 00 01 01

> HCI Event: 0x0e plen 4

  01 1C FC 00

3, Write_PCM_Data_Format_Param

[MiniBoard]# hcitool cmd 0x3f 0x1E 0x00 0x00 0x03 0x03 0x01

< HCI Command: ogf 0x3f, ocf 0x001e, plen 5

  00 00 03 03 01

> HCI Event: 0x0e plen 4

  01 1E FC 00

Then,I  Read the cyw43438 config,

1, Read_SCO_PCM_Int_Param

[MiniBoard]# hcitool cmd 0x3f 0x1d                   

< HCI Command: ogf 0x3f, ocf 0x001d, plen 0

> HCI Event: 0x0e plen 9

  01 1D FC 00 00 00 00 01 01

2,  Read_PCM_Data_Format_Param

[MiniBoard]# hcitool cmd 0x3f 0x1f

< HCI Command: ogf 0x3f, ocf 0x001f, plen 0

> HCI Event: 0x0e plen 9

01 1F FC 00 00 00 03 03 01

[MiniBoard]# 

 

The PCM/SCO is configed successfully, but the PCM_CLK is still 512KHz when I mesaure the PCM_CLK signals with an oscilloscope.

What should I do so that I can config cyw43438's PCM_CLK work at 128KHz?

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1 Solution
Zhengbao_Zhang
Moderator
Moderator

Hi Guang:

   I check the input command from you,  It is correct.   and below description is for your reference:

8kHz sampling rate with 16 bits in each PCM sample requires minimum 128-bit PCM

clock rate to support one narrowband speech channel.

Bluetooth supports maximum 3 simultaneous SCO/eSCO channels. 

pastedImage_0.png

View solution in original post

1 Reply
Zhengbao_Zhang
Moderator
Moderator

Hi Guang:

   I check the input command from you,  It is correct.   and below description is for your reference:

8kHz sampling rate with 16 bits in each PCM sample requires minimum 128-bit PCM

clock rate to support one narrowband speech channel.

Bluetooth supports maximum 3 simultaneous SCO/eSCO channels. 

pastedImage_0.png

View solution in original post