H2+/H3 Initial GPIO values (at reset time)


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Hello,

 

I am talking strictly about GPIO's value and mode at reset.

Under  "sudo gpio readall" of H3 core (OPI Lite) I can see that  ALL GPIO pins are 0V with different alternative mode functions.

Under H3 core (OPI Lite) datasheet 1.2 says that value PC3 and PC4 GPIOs are pulled up?

This are in contradiction!

 

Did anyone measured the H3 core GPIOs value? Does H3 core has any pin of pulled-up mode during the reset time of the controller?

Please help.

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Where did you found OPiLite 1.2 schematic, because I think it still 1.1 version and there is no external pullups on that board.

If you are talking about internal pullups of every GPIOs, there are only turned on by software settings, so there are not present at reset, all GPIOs for almost any SoC are usually simple high impedance floating pins.

 

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Hi Martinea,

Im a new bee in the world Orange Pi.

My promlem is I have an Orange Pi PC Plus H3 chip.

Im running Armbian Python 3 .

Im Wondering if you could kindly point me in the right direction with how to load the following:

1. all the IO  similar to Raspberry PI .

2. IBE 

3. a remote desk top like VNT in Raspberry Pi.

I could not find any Library's for the above.

I really like this board especially the WiFi Socket on the PCB.  

Thanks For your time. 

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Hello,

 

Thank you for fast notice.

"Where did you found OPiLite 1.2 schematic?"

Under official website: http://linux-sunxi.org/images/4/4b/Allwinner_H3_Datasheet_V1.2.pdf

At page 68 it is stated that GPIOs PC3 and PC4 are "Default pulled up" (at reset time).

 

Also, when I run gpio readall I get next output

=> That all are zero alue with different ALT function at reset time (with yellow in picture)

 

Am I making something wrong?

I want to trigger a LED when the micro controller is on reset faze and until the software loaded on the sd card did not started yet.

 

" for almost any SoC are usually simple high impedance floating pins" --> under Raspberry Pi you have some GPIOs that are set as OUTPUT and PULLED-UP by default in order to specifically simulate this action.

 

x.png

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46 minutes ago, Pop Andrei Lucian said:

Under official website: http://linux-sunxi.org/images/4/4b/Allwinner_H3_Datasheet_V1.2.pdf

At page 68 it is stated that GPIOs PC3 and PC4 are "Default pulled up" (at reset time).

Ok ! I see, it is not the OPiLite schematic, but the SoC H3 Datasheet.

 

Looking atthis page 68, you can see that all GPIOs are at "Z" Reset State (during Reset been asserted), this means high-impedance like I mentioned.

Also, further on page 74, even those 4 GPIOs with PullUps (which probably mean internal pullups on the pins itself, I didn't verify with a scope), have their "Default IO State" all to "DIS", means "disabled", and they stay like that until been initialized.

That is why you still seeing them with value of zero...

 

If your wish is to have a LED reflecting the fact that the chip is been resetted but no single byte read from SDCard, your only solution is to connect that LED to reset, but that doesn't mean much since a reboot won't make that LED turned on.

 

EDIT : BTW, the reason those 4 pins have internal pullups is now clear, it is because there function2 is to attached a NAND, NAND_CE1/NAND_CE0/NAND_RB1/NAND_RB0, and having those floating to unknown state would means that NAND could be corrupted, so that is why they added those special pullups directly on the pin to prevent that. This means also the "Z" on page 68 for those pins is biased.

 

EDIT2 : I've verified with my scope, and PullUps are effectively permanently there, while other GPIOs needs to be configured to get them.

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Their isn't much diffs bewtween H2+ and H3.

But as I stated above "If your wish is to have a LED reflecting the fact that the chip is been resetted but no single byte read from SDCard, your only solution is to connect that LED to reset, but that doesn't mean much since a reboot won't make that LED turned on." , I don't think your wishes can be achieve ...

 

 

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Hello,

 

Sorry for late reply, I was on vacation for a while. 

I do understand my idea is not feasible with OPI devices.

 

During reset faze I will have all my LEDs connected to GPIOs with high impedance state (Z) => Not glowing.

After reset I will run some batch script that will start my C/Python applications which will handle all the LEDs as wanted.

 

Thank you for all the support!

 

One short question. Do you know what is the maximum current driven from 3.3 V pins of OPI Zero or OPI Lite (GPIOs set as output or that two 3.3V dedicated pins)?

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Hello,

 

What do you mean by "drive strength can be changed per pin AFAIK" ??

If you have 20-40 mA on each pin and you have 17 GPIOs + 2 dedicated 3.3V pins ==> 380mA - 760mA on all pins (H2+ of OPI Zero)

 

I can see from schematic that there is only one step down circuit for 3.3V ==> that the GPIOs current is spited between this 19 pins.

 

e.g. I can power 2 pins with 60 mA / each ==> I will have 260 mA left not used.

 

Am I right?

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16 minutes ago, Pop Andrei Lucian said:

What do you mean by "drive strength can be changed per pin AFAIK" ??

I mean that in theory you can control the maximum current that can be sourced or sinked by each pin - 10, 20, 30 or 40 mA. No idea if any libraries expose these settings.

 

21 minutes ago, Pop Andrei Lucian said:

e.g. I can power 2 pins with 60 mA / each

No. 40mA per pin maximum (and I guess that defaults are not maxed out). How much current 5-3.3v step-down regulator can supply is another consideration, schematic says it's 0.8-1A, and this includes all SoC I/O pins, not only those that are exposed on the pin header.

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