CH341a and logic level converter

[megaraider]

Re: CH341a and logic level converter

(...)On SPI chip you have serial data out and serial data in,clock etc.
And all are uni-directional.
Is not like in i2c where you have one pin clock one pin data.
That require bidirectional converter.

True... but only in Standard SPI mode!
But most devices now support Dual, Quad, ... SPI mode for access speed improvement!
Since one's not sure about the programmer algorithm,
what SPI mode is being used, it's better to be sure than sorry

[gabiz_ro]

Re: CH341a and logic level converter

Indeed.
But if programmer doesn't work in dual or quad mode but in standard SPI mode then?
Isn't same content?
Still works but at lower speed?

[wall]

Re: CH341a and logic level converter

After all this time my tablet is still a paperweight due to never getting the programmer to work. I think the programmer is dead, Windows recognizes and installs the drivers correctly but the LED lights don't turn on and the software says Device State: NotConnected in the bottom right corner

[stj]

Re: CH341a and logic level converter

check the jumper is in "programmer" mode and not "serial" mode.

btw, pro convertor for low voltage parts.
http://www.ebay.co.uk/itm/191899183629

[wall]

Re: CH341a and logic level converter

I tried the jumper on 1-2 and 2-3, it shows in device manager either way but never turns the leds on and the software never detects it.

[stj]

Re: CH341a and logic level converter

so what version of windows is it, and what is it recognised as?

[wall]

Re: CH341a and logic level converter

USB-SERIAL CH341A. Installs automatically under Windows 10 and it's exactly the same driver I have to manually install in Windows 7.

[stj]

Re: CH341a and logic level converter

and the parallel drivers?

[wall]

Re: CH341a and logic level converter

There is no other device to install.

[stj]

Re: CH341a and logic level converter

the chip is a usb to parallel converter aswell as a usb to serial convertor.

i'm starting to think it's a windoze problem as usual.

[wall]

Re: CH341a and logic level converter

But it should power the LEDs at least, the board gets hot under the chip. Could I have burned it by connecting it to the bios chip on the tablet without removing the battery?

[stj]

Re: CH341a and logic level converter

your supposed to remove the damned bios first, you probably tried to power the entire tablet through the programmer!!!

anyway, it probably survived.
i will try to set one up on xp later and see what the o.s. says and what the led's do.

[megaraider]

Re: CH341a and logic level converter

wall

If the CH341 programmer power led doesn't light up upon connection to the USB port the programmer is, imo, burned or dead.
Buy another one... trying to avoid spending less than 5€ and remaining with a dead tablet is not a solution

Found this tutorial in pdf:
Recovering-a-Bricked-Chuwi-Hi12-caused-by-Corrupt-Bios.pdf

and these videos:
https://www.youtube.com/watch?v=-K8Xif-6GUw
https://www.youtube.com/watch?v=0WHJgi1U5bc

Everything you need is there » Follow them step by step

Do not forget to:
- isolate / disconnect w25q64fw pin 8 (bios chip) from the programmer;
or
- disconnect the red wire that connects the battery to the board;

.

[wall]

Re: CH341a and logic level converter

Some people succeeded in flashing these Cherry Trail tablets without desoldering the bios or disconnecting the battery and even without a 1.8v converter.
What's the worse that could happen if I don't isolate the VCC pin? I already put 3.3V through it and probably eveything in between VCC and GND that's meant to take 1.8V, the tablet is behaving the same, still charges the battery and powers devices through the usb host.
I really don't want to desolder the bios chip or even bend a leg back.

[megaraider]

Re: CH341a and logic level converter

Yes, you've already temp fate
If the tablet still behaves as before and a close naked eye inspection doesn't reveal anything burned lets assume the only casualty is the programmer

You don't have to remove any solder or bend any pin.
Just use isolation tape on bios chip pin 8 placed between the pin itself and the contact on the clip, thus isolating w25q64fw pin 8 (bios chip) from the programmer

.

[wall]

Re: CH341a and logic level converter

Should I buy another CH341a? I was thinking about trying the EZP2010 but I only see "W25X64" in the manual and "W25Q64BV" in the software. Do you think it will work?

[wall]

Re: CH341a and logic level converter

I received my new CH341a, this time not the black one and the mentioned 1.8V SPI converter, but the software can't detect the chip, I programmed it twice anyway but the tablet still doesn't turn on, this was with the BAT+ desoldered, by the way.
So I should really remove the bios chip, what puzzles me is that everywhere I looked nobody removed the battery or desoldered the chip from the motherboard and they were all successful wih those sh*tty clips.

[diif]

Re: CH341a and logic level converter

It takes less time to remove the BIOS chip than it does messing about with those clips ensuring they are making proper contact.
Removing it and soldering it directly to the CH341a is the best way as you will know for sure. It's possible the chip is faulty.

[wall]

Re: CH341a and logic level converter

It has too many small resistors, memory chip and emmc right next to it I don't know how the hell I'm going to desolder this..

[diif]

Re: CH341a and logic level converter

Hot air.