topic i.mx6ull question in i.MX Processors

i.mx6ull question

strive — Sat, 03 Jun 2017 11:46:38 GMT

Dear Expert:

About i.mx6ull-evk，I have questions below,please help answer,thanks.

1. this picture is from the MCIMX6ULL-CM Page 10:

a. what function is this signal "GPIO_DVFS"?

b. Is ther a current size requirement about Q702 and Q707? If yes, is the 230mA enough?

c.Q701 is different Q702 and Q707,is there any special?

2. this picture is from the MCIMX6ULL-CM Page 10 too:

could you tell me whether this circuitry is software watchdog or not?How work?

C738 is a capacity, how is this signal "nWDOG" control UM805RE?

pls help,thanks.

Re: i.mx6ull question

igorpadykov — Sun, 04 Jun 2017 23:00:16 GMT

Hi Tom

-GPIO_DVFS implements changing arm core voltage for cpufreq driver
-there is no special size requirement for Q701,702, as for Q707 it discharges
VDD_ARM_SOC_IN voltage so may be recommended to use the same type
as used on EVK
-MCIMX6ULL-CM Page 10 implements board reset function used for software
reboot, it is the same solution as for i.MX6Q Sabre SD board spf-27392 p.21,
that is toggle all power board for reliable reboot.

Best regards
igor
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Re: i.mx6ull question

strive — Mon, 05 Jun 2017 00:51:52 GMT

Dear Expert:

thanks for your answer.

Furthermore:

1. how to comprehend?

what change is the DVFS when system reboot?

2. in this picture,C738 is a capacity,so could you tell me What is the Electrical property of the signal nWDOG,pulse or level,and is this need the software to controll?

thanks for your support.

BRs

Tom

Re: i.mx6ull question

igorpadykov — Mon, 05 Jun 2017 05:46:43 GMT

Hi Tom

DVFS may lower voltage so processor will not reboot.

For example , if just before reboot it is under lowest cpu freq setpoint ,

low voltage can not make system boot up at default frequency (as after power-up).

For nWDOG there is no software to control of pulse or level.

~igor

Re: i.mx6ull question

strive — Thu, 08 Jun 2017 07:59:39 GMT

Dear Expert:

OK,thanks for your support.

BRs

Tom