I.MX8M MINI Power Up Sequence

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I.MX8M MINI Power Up Sequence

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sameer_pitre
Contributor II

Hi,

I have query regarding i.MX8 M MINI power ups sequence. If you look at the power up sequence timing, 

pastedImage_2.png

1. The minimum timing mentioned is '0' . Does that mean all supplies can come at once ?

2. Does RTC clock and RTC_RESET_B are must for serial download mode ? 

I have another query which is related to serial download mode using USB. I am using USB1 as device only. I am not using USB_ID pin. This should not create any issue for serial download mode, right ? Second question is regarding USB_VBUS. According to i.MX8 datasheet, it should be 3.3V max. But if you see the NXP i. MX 8M MINI EVK board, it is at 5V level ( comparator  is used to generate this voltage ). Need some clarification on this.

 

Thanks,

BR,

Sameer

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4 Replies

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Rita_Wang
NXP TechSupport
NXP TechSupport

Hi Sameer,

1. Not All. For example T1, means NVCC_SNVS_1P8  and VDD_SNVS_0P8 can come at once.

2. Yes

USB_ID floating is no problem.

There is an external resistor R108 . 30K  so that the USB1_VBUS pin gets a lower voltage.

8MM-usb.png

Have a nice day

Rita

 

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henry4
Contributor I

Hi,

Regarding this topic I have two questions to ask. 

1. I measured the timing parameter of the power on and off sequence but it differs from the NXP manufacturer's data sheet (PMIC part: PCA9450AAHNY; CPU part: MIMX8MM3CVTKZAA). Is there a problem with I.MX8M when there is such a discrepancy?

- Power-up sequence:

henry4_3-1696319298627.png

 

henry4_1-1696319143886.png

- Power-down sequence:

henry4_5-1696319377770.png

henry4_6-1696319411453.png

2. How can I fix this if I want the power-up sequence and power-down sequence times to be the same as the data sheet that NXP provides?

Thanks,

Henry

 

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sameer_pitre
Contributor II

Hi Rita,

Thanks for your support. My issue is resolved. I can now successfully flash my board using USB as device.

Regards,

Sameer

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Rita_Wang
NXP TechSupport
NXP TechSupport

OK. I am glad to hear that.

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