i.MX6Q: RTC_XTALI voltage from VDD_SNVS_IN

[norishinozaki]

Hello Champs,

I found a following description in RM page 37.

"The OSC32k runs from VDD_SNVS_CAP, which comes from the VDD_HIGH_IN/VDD_SNVS_IN power mux. The target battery is a ~3 V coin cell."

From "Table 6. Operating Ranges", VDD_SNVS_IN is from 2.8V to 3.3V.

However in "Table 21. XTALI and RTC_XTALI DC Parameters", 32KHz RTC_XTALI Vih max is 1.1V.

How should I consider the voltage for RTC_XTALI?

Best regards,

Nori Shinozaki

[唯唯胡]

​where are you?

[Yuri]

Hi,

   The  VDD_SNVS_IN is input voltage for internal regulator (providing  VDD_SNVS_CAP).

Regards,

Yuri.

[norishinozaki]

Hello Yuri,

Thanks, now I understand I need to look for VDD_SNVS_CAP.

But I can't find the DC spec..

Best regards,

Nori Shinozaki

[igorpadykov]

Hi Nori

RTC_XTAL is powered from VDD_SNVS_CAP so voltage level of this driving clock

should not exceed the voltage of VDD_SNVS_CAP (about 1V value). This is

described in Table 2-7. Oscillator and clock recommendations

i.MX6 System Development User’s Guide (rev.1, 6/2013)

http://cache.freescale.com/files/32bit/doc/user_guide/IMX6DQ6SDLHDG.pdf

Best regards

igor

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[norishinozaki]

Hello Igor,

I couldn't find out VDD_SNVS_CAP is about 1.0V

The customer is askinf for detailed DC spec of VDD_SNVS_CAP and NVCC_PLL_OUT, expecially for output current performance, because they are designing external clock circuts to provide 24MHz and 32KHz.

Is there any specs for output current?

Also they are looking an example design for external clock circuit.

Please send me if you have one.

If not, could you advise how to provide power to RTC_XTALI and XTALI.

I found "Optional LDO" design in the i.MX6QSabreSD schematics.

Do you need add LDO like this?

Best regards,

Nori Shinozaki

[igorpadykov · Accepted solution]

Hi Nori

VDD_SNVS_CAP value is given in Table 8-1. Sample voltage report

i.MX6 System Development User’s Guide (rev.1, 6/2013)

http://cache.freescale.com/files/32bit/doc/user_guide/IMX6DQ6SDLHDG.pdf

there are no specs for output current, because they are not intended for external

loads.

Best regards

igor

[norishinozaki]

Hello Igor,

Thanks, I found a word "VDDSNVS_CAP" in the HDG finally!

Best regards,

Nori Shinozaki

[唯唯胡]

你在苏州吗？可以的话我找你寻求下帮助，我是苏大的学生

[norishinozaki]

你好 唯、

我在东京。

非常遗憾、我没说汉语。

总之、太感谢了!

[唯唯胡]

You are welcome. Have you ever used K64 MCU？Besides,do you use some other communication tools? I have some technical problems about USB to ask you. I you have spare time, i expect your repy.

Yours Sincerely.

[norishinozaki]

Hello,

Sorry but I'm i.MX FAE,  I don't know about K64.

加油！