Help to discover what MCU is used on USB Biometric Fingerprint Attendance Machin

[acassis]

Hi Everybody,

I bought a chinese USB Biometric Fingerprint Attendance Machine similar to this:

KKmoon 2.8" TFT LCD Display USB Biometric Fingerprint Attendance Machine Password Time Recorder Clocking Employee Checking-in Reader

https://www.amazon.com/KKmoon-Biometric-Fingerprint-Attendance-Checking/dp/B071NRN3S9

I tear down the plastic cover and noticed that there is not label printed on microcontroller.

Maybe based on the following info some smart people here could infer what the microcontroller is:

Package: LQFP80

Small LCD display connected between pins 26 and 37 (info in the LCD: BL-B40023A NX-2403A 2017/12/18)

32KHz crystal on 42 and 43

12MHz crystal on 56 and 57

USB D+ 45
USB D- 46

Please see attached picture of the board for reference.

BR,

Alan

[amyk]

Unless you happen to find someone here who has used that exact MCU, everyone else can only do the same thing you can: Google for datasheets with things like "USB MCU QFP80" and compare pinouts.

As far as I can tell with a bit of the above, it is not any of the following

- NXP KL21, KL22, or KL27 series
- PIC32MX
- PIC18
- SAM D21


(Sometimes I wish there was an easy "lookup by pinout" search engine... having done a similar thing many times before.)

[abyrvalg]

Reading out that 8-pin serial flash could help too.

[lucazader]

My 2c:

Almost definitely isnt an STM32 processor, they dont come in LQFP80's from what i know of.

[Gribo]

It can be an MSP430F5xx
HF, LF, USB, LQFP80.

[amyk]

It can be an MSP430F5xx
HF, LF, USB, LQFP80.

Pinout doesn't match.

[acassis]

Thank you guys for all these suggestions.

Yes, in fact I already search for USB MCU LQFP80, also when to Mouser and filtered for MCUs with LQFP80 pinout and analyzed their datasheet, but no luck.

I suppose it is some Chinese MCU that we don't know about its existence yet.

[carl0s]

Thank you guys for all these suggestions.

Yes, in fact I already search for USB MCU LQFP80, also when to Mouser and filtered for MCUs with LQFP80 pinout and analyzed their datasheet, but no luck.

I suppose it is some Chinese MCU that we don't know about its existence yet.

I appreciate the pinouts don't match, but do you think it could be an ASIC rather than a general purpose MCU ? Such as this: http://www.synochip.com/var/upload/file/20140506/13993377497584.pdf

Wouldn't fingerprint ID take a lot of power, unless that was built into the scanner part of it?

[funkathustra]

What is the VID the device instantiates as? Many small shops just use the MCU manufacturer's VID.