the clock output is not correct in HSRUN mode

[RehabSoliman]

Hello all 

I am using s32k142 EVB and configure the clock to run in HSRUN mode and I want to be sure that the clock output is correct but I found that It is not correct. I am using the internal oscillator not the external.

if the s32k142 doesn't have external oscillator on the board?

If I use wrong test please tell me the correct test to be sure that:

• configure the HSRUN mode with :
• SPLL = 112 MHz
• Core & System clocks  = 112 MHz (their input must be the SPPL)
• Bus clock = 56 MHz

and I will attach the code to test the clock please help me in this issue     

[Robin_Shen]

Hi RehabSoliman,

I am using s32k142 EVB and configure the clock to run in HSRUN mode and I want to be sure that the clock output is correct but I found that It is not correct.

The method of flipping IO is imprecise. SCG_CLKOUTCNFG[CLKOUTSEL] and SCG_CLKOUTCNFG[CLKOUTSEL] can output clock on the CLKOUT pin.(Do not forget select the CLKOUT in pins tool) 

I am using the internal oscillator not the external.

But the clock_configuration.png shows that you select external 8MHz crystal as input of SPLL_VCO.

Best Regards,
Robin
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[RehabSoliman]

Thanks for your reply 

but I mean I want to be sure that the frequency is 112MHz so I need a way to test this part.

 I want to Check system clock speed (main clock speed) is 112MHz

is the s32k142EVB has external oscillator on the board?

[Robin_Shen]

Did you output the clock by refer SCG_CLKOUTCNFG[CLKOUTSEL] SPLL_CLK.png? What is the frequency measured by the oscilloscope on the CLKOUT pin?

S32k142EVB has external 8MHz crystal on the board, just like the project configured.

[RehabSoliman]

the clock out is 112MHz

but I want to be sure that the core clock and system clock is 112MHz

[Robin_Shen]

Did you tried to select HCLK output CORE_CLK?

[RehabSoliman]

No, I didn't because I don't know how to this 

could you tell me the steps and I will try to do ?

[Robin_Shen]

This way you can output SPLL_CLK at CLKOUT pin.

the clock out is 112MHz
I am not sure if you achieve it(output SPLL_CLK at CLKOUT pin). Did you select which pin as CLKOUT? Are you able to measure the frequency by using oscilloscope?)

The method is the same, edit settings of SIM_CLKOUTSEL and select HCLK.

[RehabSoliman]

I did this test and the spll is 112MHZ but I want to be sure that the core clock has 112MHz not 48MHz 

could you help me in this part?

[Robin_Shen]

I did not configure the Core to 112 MHz in last reply, so even if I choose CLKOUT that image shows 48MHz. I'm not sure if you have modified the core frequency to 112MHz, what is the frequency of CLKOUT output by the oscilloscope now?

In below image, you can see the core clock is configure to 112MHz and the CLKOUT(HCLK selected) will be 112MHz. I am not sure if you notice the note1 in Figure 27-1. Clocking diagram: 1. The source of HCLK (to Arm® Cortex® modules) is CORE_CLK.

[RehabSoliman]

Hello 

I get it finally but it sine wave not square wave is it wrong ?

[Robin_Shen · Accepted solution]

I don't think it's wrong. The output 112MHz signal may be too high frequency. In addition, the oscilloscope bandwidth of 350MHz may be too low.

[RehabSoliman]

thanks for your support

[RehabSoliman]

the output = 40.98360655737705 MHz 

it is not correct I think I have something wrong in the configuration

I attached the configuration could you take a look to help me ?

[RehabSoliman]

I want to know is it mandatory to use power manager when I want to set the HSRUN mode 

or it is not related because if I turn the power manager the HSRUN mode not work