Compatability with new Imax B6 clones - "New B6 v2.1 20220706"

[Tim Small]

Hi,

I recently got a B6 clone.  I'd like to do NiMH charging with delta T, so I trust Cheali more than the stock firmware.  The board looks quite different to the ones on github.  I can't see the micro controller because it is under the display (which would need to have 16 though-hole pins desoldered to remove it).  The PCB has the designator "New B6 v2.1 20220706" on the silk screen.  Construction quality looks good, with SMT components down to 0402 size.

There are two headers which looks like they could be programming headers.  Both are 5 pin - one is closer to (which I think is) the mcu on the top edge, and is unpopulated - "J3".  

The other is near the bottom edge of the board further from the mcu, and is also an unpopulated through-hole, but has the holes filled with solder.  Looks like there are probe impressions in the solder, so I guess that's from the factory, but it could either be programming or some sort of functional test on the power electronics side.  That would make sense if the mcu is pre-programmed before being placed on the PCB I suppose...

Peering under the LCD, I can see a 48 pin chip (TQFP package), and a 14 pin (SOIC ?).  The 48 pin one is nearest to J3.

Any thoughts?

Cheers,

Tim.

[Tim Small]

Here is a top-of-PCB photo.

I can just about see an ST logo on the MCU, so maybe its an STM32F103 (or more likely clone) - which would fit with the 48 pins.

[Roberto Garcia]

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To check the processor , you need to unscrew both bolts from the screen and do a little bend to see ...

That charger, as you said have two 5 pin header. One on the top near screen, to program the CPU.

The other 5 pin header is very interesting. This header is used to eliminate the 4 push buttons and install a keypad or something to do the 4 functions "remotely".

The 14 pin chip could be the multiplexor.

This multiplexor works with the 6 cell  balance port and the temperature to the CPU .

According to this cheali charger stuff, if the CPU is unknown , chances are you will destroy it if you do the flashing.

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[Roberto Garcia]

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Well , at least is a STM32 something...

Check very carefully the CPU list to see if the flashing thing could be doing without destroy...

As far as I know, the big difficulty is that the traces coming out the CPU run differently on clone than the original.

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El mar, 27 de feb. de 2024 8:10 a. m., 'Tim Small' via cheali-charger <cheali-...@googlegroups.com> escribió:

Here is a top-of-PCB photo.

I can just about see an ST logo on the MCU, so maybe its an STM32F103 (or more likely clone) - which would fit with the 48 pins.

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[Roberto Garcia]

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I did this drawing...

Base on my experience with this excellent charger.

I hope this would help you.

El mar, 27 de feb. de 2024 8:10 a. m., 'Tim Small' via cheali-charger <cheali-...@googlegroups.com> escribió:

Here is a top-of-PCB photo.

I can just about see an ST logo on the MCU, so maybe its an STM32F103 (or more likely clone) - which would fit with the 48 pins.

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[diggit]

Hi,

If it's STM8, then it's no-go for cheali. STM32s are currently not supported, but it's doable if someone puts their time into it.

For example I don't have enough motivation for adding support of https://github.com/stawel/cheali-charger/issues/340  because I don't like the low cost HW there (no diff amps for balancer).

I am also struggling with motiovation to finish support for more powerful, but still affordable device here https://github.com/stawel/cheali-charger/issues/338

Roberto:

BTW these chargers have buck/boost smps and "discharge resistor" is only current sensing shunt. Most power dissipatey discharge transistor.