Picofly AIO Thread

[abal1000x]

.

 

[deeps]

Finally, I can get out of my sick bed and back to my Personal R&D Headquarter (my beloved bedroom). During my sick leave, there are lots of thing has changed/updated with Picofly scene.
Good news is I have completed testing cable for Picofly (fab it with JLCPCB and share them among my friends who are able to do hardware mod with their machine). Cable works perfectly. Beside JLCPCB, I already try with oshpark and nearly 2 months, I haven't received them yet
View attachment 373305
Bad news is I can only support Mariko variant due to not having V1 around. But I am willing to adjust if someone can give me dimension.
Some pictures:
View attachment 373303
View attachment 373304

P/s: Tidy something up and will upload them on github
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Note1: According to another thread, I will add 1k ohm resistor between Source and Gate pin.

This loooks great! But... it's spelled homebrew

 

[cgtchy0412]

hwfly use np2016 which is 9mohm, and they use it parallel so its become 4.5mohm when both the gate open. Which is still prettly low.

Yeah just looked the specs now, i must have misread somewhere.

The pulldown resistor is advisable because lot of people reporting BSOD cases. Which might be caused by the mosfet. But for me, i am not convince that the mosfet open state is the cause of BSOD.

To be precise BSOD after working before, happen once on me. Acctually if we test and close some mosfet or maybe all mosfet with like multimeter then it will stay on for a while and we need to just touch it or grounding it to make it open again.

Also is there any code in the firmware that cut off/turn off the power in pico after sucessfull glitch? to make it completely disabled upon boot.

 

[abal1000x]

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[Danook28]

 

[abal1000x]

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[Danook28]

 

[lenoa]

Just to fulfill my promise.

Not Work/ Not Strong Enough to Glitch
AON7400A, It give false positive so cannot work reliably, one unit returned from customer with systomp can only boot to stock.
AON6414A

Works, Reliable But large package 5x6, Single Mosfet Install
AON S36312
AON 6512
AON 6792
Acctually as it is large the soldering is simpler, but for facedown install you need to cut the shield bridge between apu and ram, or better if you can solder it faceup and just slipped it under the bridge.

Works, Reliable, Perfect 3x3 package, Single Mosfet Install
FDMC 7672

All test were done on Lite&V2
Im now currently using AON S36312 for instalations.

mine 6414 good for now

 

[zorusgb]

You can also try this approach by @abal1000x adding the resistor in Pico between CPU point and Boot button's lower solder pad (Ground)
I don't know if it works but looks interesting

If I'm reading it correct this is actually 680 Ohm resistor which is below the recommended 1k.

 

[abal1000x]

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[calishooter]

My OLED is currently on v2.65 with no issues...do I really need to update to v2.73?
I was thinking just to update to v2.66 for proper fuse burn. What do you guys think?
Thanks!

 

[QuiTim]

I roughly calculated like this:

From the datasheet IR8342
Max Vgs 20V
View attachment 373375

Then the power rate of the resistor
View attachment 373378

If i use 0805 resistor with 0.1W, then the max current will be at 100/20 = 5mA. So i need minimum R = 20/5 = 4kOhm
If i use 1210 resistor with 0.25W, then the max current will be at 250/20 = 12.5mA. So i need minimum R = 20/12.5 = 1.6kOhm
If i use 2512 resistor with 0.5W, then the max current will be at 500/20 = 25mA. So i need minimum R = 20/25 = 800Ohm

But the capacitance is only 1000pF
View attachment 373379
If the Voltage 20V then for 1000pF, it have charge Q = CV = 1000x20 = 20nC.
Lets say 500mA will break those resistor, then the time to discharge roughly will be around t = q/i = 20/500 = 40nsec.
This range of time wont break the resistor.

Practically just use whatever resistance you have at hand, will be enough to discharge those 1000pf.

But then we need to consider the rp2040 electrical properties of the gpio.
View attachment 373383
It is pull down by between 50-80k ohms. Our pulldown mosfet will be paralled by this.
So don’t use resistor >50kOhm. Because using aournd this value, will reduce the resistance significantly, which might split the voltage (voltage divider) enough so that the high voltage will be decrease into the range of the low voltage.

So in conclusion, just pick any resistor you have at hand approximately below 5kOhm.

That was nice

 

[karatefeet]

Ok, I installed today with 2.73 FW on a lite switch, classic installation, 1 mosfet, I didn't add resistor on mosfet, I didn't solder sda, scl either.
Everything starts instantly.
So, can I avoid adding?

Wow really nice soldering job! What mm wire are you using for the mosfets? 0.2 mm twisted together?

 

[QuiTim]

If I'm reading it correct this is actually 680 Ohm resistor which is below the recommended 1k.

abal1000x already explaind it

 

[INeFFeCTiVE]

What is the best way to remove the USB C header from the WaveShare RPI2040-Zero? The buttons were easy to remove, but the USB C connector is really in there.

 

[zorusgb]

I roughly calculated like this:

From the datasheet IR8342
Max Vgs 20V
View attachment 373375

Then the power rate of the resistor
View attachment 373378

If i use 0805 resistor with 0.1W, then the max current will be at 100/20 = 5mA. So i need minimum R = 20/5 = 4kOhm
If i use 1210 resistor with 0.25W, then the max current will be at 250/20 = 12.5mA. So i need minimum R = 20/12.5 = 1.6kOhm
If i use 2512 resistor with 0.5W, then the max current will be at 500/20 = 25mA. So i need minimum R = 20/25 = 800Ohm

But the capacitance is only 1000pF
View attachment 373379
If the Voltage 20V then for 1000pF, it have charge Q = CV = 1000x20 = 20nC.
Lets say 500mA will break those resistor, then the time to discharge roughly will be around t = q/i = 20/500 = 40nsec.
This range of time wont break the resistor.

Practically just use whatever resistance you have at hand, will be enough to discharge those 1000pf.

But then we need to consider the rp2040 electrical properties of the gpio.
View attachment 373383
It is pull down by between 50-80k ohms. Our pulldown mosfet will be paralled by this.
So don’t use resistor >50kOhm. Because using aournd this value, will reduce the resistance significantly, which might split the voltage (voltage divider) enough so that the high voltage will be decrease into the range of the low voltage.

So in conclusion, just pick any resistor you have at hand approximately below 5kOhm.

Someone was paying attention in class. Nice write-up abal. In this case what do you say would be the lowest resistance that can safely be used, regardless of the power rating of the resistor?

 

[karatefeet]

To be precise BSOD after working before, happen once on me. Acctually if we test and close some mosfet or maybe all mosfet with like multimeter then it will stay on for a while and we need to just touch it or grounding it to make it open again.

Were you able to fix the BSOD? Tried my first install with a single mosfet on a Lite this weekend and resulted in BSOD. I've done v2 and lites with the cpu flex without any issues previously.

 

[zorusgb]

What is the best way to remove the USB C header from the WaveShare RPI2040-Zero? The buttons were easy to remove, but the USB C connector is really in there.

Most people use heat gun or a reflow station

 

[QuiTim]

What is the best way to remove the USB C header from the WaveShare RPI2040-Zero? The buttons were easy to remove, but the USB C connector is really in there.

If you have a hot air station, just add kapton tape to components around and heat the USB connector.
If you don't then your best bet is flux and wick/braid wire and preferably some low melt solder.
First you add some flux and low melt solder to every part of connector.
Then you take the wick and add some more flux to it and then drag the wick and solder through the pads and in the end on the 4 anchors, so you basically suck up as much solder as you can.
If done right (with good flux, solder wire and good wick) you should be able to lift it up clean.
If you get a stubborn connection lift the connector carefully with tweezers and touch the point that is still connected with the soldering iron.

 

[INeFFeCTiVE]

I wish I had a hot air station. Its me, a Pinecil with the stock tip and the 2 mentioned in the guide, and some flux. I can braid up a wick real quick (done it before), and use what I got on hand for solder... I was just hopping for some magic trick that someone had come up with. Thanks for the help!