How to configure LPC43xx PLL0AUDIO frequency

samchen_tw — Tue, 21 Aug 2018 09:27:44 GMT

Hi all

I am using om13088 development board, and try to configure clk0-pll0audio clock to 512fs where fs is 48kHz.

I am follow here to setup pll.

https://www.nxp.com/docs/en/user-guide/UM10503.pdf

Here is my configuration in board.c

static const CGU_USBAUDIO_PLL_SETUP_T audioPLLSetup = {
0x0000601D,
0x0 ,

0x0000201d ,
0x16872b,
24576000\
};

Chip_SCU_PinMuxSet (0x6, 0, (SCU_PINIO_FAST | SCU_MODE_FUNC4)); /* I2S0_RX_SCK */
Chip_SCU_PinMuxSet (0x6, 1, (SCU_PINIO_FAST | SCU_MODE_FUNC3)); /* I2S0_RX_WS */
Chip_SCU_PinMuxSet (0x3, 5, (SCU_PINIO_FAST | SCU_MODE_FUNC5)); /* I2S0_TX_SDA */
Chip_SCU_PinMuxSet (0x3, 2, (SCU_PINIO_FAST | SCU_MODE_FUNC1)); /* I2S0_RX_SDA */
Chip_SCU_PinMuxSet (0x3, 1, (SCU_PINIO_FAST | SCU_MODE_FUNC0)); /* I2S0_TX_WS */
/* set clk0 function to CLKOUT and clk0 is connected to PLL0-AUDIO */
Chip_SCU_ClockPinMuxSet(0,(SCU_MODE_FUNC1|SCU_MODE_INACT));
/* Setup base clock for CLKOUT */
Chip_Clock_SetupPLL(CLKIN_IRC, CGU_AUDIO_PLL, &audioPLLSetup);
Chip_Clock_EnablePLL(CGU_AUDIO_PLL);
Chip_Clock_SetBaseClock(CLK_BASE_OUT, CLKIN_AUDIOPLL, false, false);

The output frequency with above setting is 48Mhz

Dose anyone have ideas about how to set pll0audio?

Thanks.

Sam

Re: How to configure LPC43xx PLL0AUDIO frequency

soledad — Thu, 06 Sep 2018 16:16:44 GMT

Hi,

You can use the Audio PLL settings calculation tool please check the following link:

Audio PLL settings calculation tool.zip

In addition check the following link:

PLL0 PDEC calculation

Have a great day,
Sol

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How to configure LPC43xx PLL0AUDIO frequency

Re: How to configure LPC43xx PLL0AUDIO frequency