SK-AM62-LP: [Audio][McASP] Configuring external clock for McASP

Muhammadh Salih

Part Number: SK-AM62-LP
Other Parts Discussed in Thread: SYSCONFIG, AM67

Tool/software:

Hi,

We are using the TI processor SDK ti-processor-sdk-linux-am62xx-evm-11.00.09.04. We are customizing the BSP Audio configuration for our custom hardware. Below is the pin configuration for McASP interface:

`RGMII2_RD3 (AE22)`	`256XFS`	`Input`	`AUDIO_EXT_REFCLK0`
`RGMII2_RD1 (AB20)`	`TUNER_I2S_WS`	`Input`	`MCASP2_AFSR`
`RGMII2_RXC (AD23)`	`TUNER_I2S_TX`	`Input`	`MCASP2_AXR1`
`RGMII2_TD1 (AA18)`	`TUNER_I2S_CLK`	`Input`	`MCASP2_ACLKR`
`RGMII2_RD2 (AC21)`	`TUNER_SD_IN0`	`Output`	`MCASP2_AXR0`
`RGMII2_TD2 (AD21)`	`TUNER_WS_IN0`	`Output`	`MCASP2_AFSX`
`RGMII2_TD3 (AC20)`	`TUNER_BCK_IN0`	`Output`	`MCASP2_ACLKX`

Here, We are trying to configure the pins in TI systool. The configuration for AUDIO_EXT_REFCLK0 pin not visible in TI systool.

mymcasp2_pins_default: mymcasp2-default-pins {
pinctrl-single,pins = <
AM62X_IOPAD(0x0170, PIN_INPUT, 2) /* (AA18) RGMII2_TD1.MCASP2_ACLKR */
AM62X_IOPAD(0x0178, PIN_INPUT, 2) /* (AC20) RGMII2_TD3.MCASP2_ACLKX */
AM62X_IOPAD(0x0188, PIN_INPUT, 2) /* (AB20) RGMII2_RD1.MCASP2_AFSR */
AM62X_IOPAD(0x0174, PIN_INPUT, 2) /* (AD21) RGMII2_TD2.MCASP2_AFSX */
AM62X_IOPAD(0x018c, PIN_INPUT, 2) /* (AC21) RGMII2_RD2.MCASP2_AXR0 */
AM62X_IOPAD(0x0180, PIN_INPUT, 2) /* (AD23) RGMII2_RXC.MCASP2_AXR1 */
>;

Please let me know why this pin is not showing in the TI Systool. Also, we want to know how this AUDIO_EXT_REFCLK0 will be used by the Codec driver (we are using dummy driver). Is there any properties need to set it in DTS?

Here, there is some clocks going input to the SOC and vice versa. How the data will be sampled? Whether with this AUDIO_EXT_REFCLK0 clock for both the clocks.
Please let me know your inputs on the same

Thanks in advance.

Regards,
Salih

2 months ago

0 Suren Porwar 1 month ago

TI__Mastermind 28235 points

Hi Salih,

Can you share the entire DTS file that you have with your modifications? Also, I understand you are trying to use a dummy codec. But How are the clocks being generated for MCASP2? Are you trying to provide an external clock source to AUDIO_EXT_REFCLK0?

Best Regards,

Suren

0 Muhammadh Salih 1 month ago in reply to Suren Porwar

Intellectual 320 points

Hi Suren Porwar,

Below are the changes we did it in DTS. Since, the custom hardware is not yet ready. So, we are trying to do some experiments with EVM board.

        codec_test: codec_test {
                compatible = "linux,snd-soc-dummy";
                #sound-dai-cells = <0>;
                status="okay";
        };

codec_audio: sound {

                compatible = "simple-audio-card";
                simple-audio-card,name = "J784S4-TEST";
                simple-audio-card,format = "i2s";
                simple-audio-card,bitclock-master = <&sound_master0>;
                simple-audio-card,frame-master = <&sound_master0>;

                sound_master0: simple-audio-card,cpu {
                sound-dai = <&mcasp1>;
                system-clock-direction-out;
                };

                simple-audio-card,codec {
                        sound-dai = <&codec_test>;
                };
        };

We are having two McASP lines for this Tuner chip. One is input for SOC and the other one is output for SOC.
Please provide your suggestion on this.

Thanks in advance.

Regards,
Salih

+1 Suren Porwar 1 month ago in reply to Muhammadh Salih

TI__Mastermind 28235 points

Hi Muhammadh,

I have tried to answer few queries pertaining to making MCASP as master and how the BCLK and Frame Sync can be generated in the below few threads.

Please review them and hopefully you should be able to use the Clock tree tool to understand the clocking on MCASP as well.

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1519789/am623-sk-am62b-p1-mcasp-issue

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1487650/am625-running-mcasp-as-master-with-external-audio_ext_refclk-of-24-576mhz

If upon going through these threads, you are able to modify the DTS file that includes assigned-clocks, assigned-clock-parents etc, we can review your DTS file.

Hope this helps

Best Regards,

Suren

+1 Muhammadh Salih 1 month ago in reply to Suren Porwar

Intellectual 320 points

Hi Suren,

Thanks for your inputs. How to configure the below pin in the TI Sysconfig tool:

Because, there is no option available to configure AE22 pins as AUDIO_EXT_REFCLK0 mode in sysconfig tool.
Currently, we are manually configuring it in our DTS file for testing.

Please let me know your inputs on the same.

Regards,
Salih

0 Suren Porwar 1 month ago in reply to Muhammadh Salih

TI__Mastermind 28235 points

Hi Salih,

On the sysconfig tool you should be able to see the AUDIO_EXT_REFCLK0/1 under system.

See the screenshot below:

Hope this helps

Best Regards,

Suren

0 Evan Williams 1 month ago in reply to Muhammadh Salih

Intellectual 550 points

Hi Muhammadh,

Where did you find this pin configuration document? I'm looking for a similar setting on the AM67 missing from the pin configuration tool

Thanks

0 Suren Porwar 1 month ago in reply to Evan Williams

TI__Mastermind 28235 points

Hi Evan,

The PIN configuration should be available in the datasheet.

Best Regards,

Suren

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SK-AM62-LP: [Audio][McASP] Configuring external clock for McASP