EEVblog Electronics Community Forum

Electronics => Microcontrollers => Topic started by: Atom on September 17, 2019, 05:15:12 pm

Title: Multimeter EEPROM modding Zeast282 RX/TX enabling
Post by: Atom on September 17, 2019, 05:15:12 pm
hello! first time posting in the micro section..

So the problem here is that i bought 2 Zeast 282 multimeters for dirt cheap 12e each, the thing is that i'v seen some multimeters have a serial out functionality and that could be very useful for datalogging, + i can learn something about eeproms and the ch341 programmer that has been sitting in the bag in which arrived for over a year

so the zeast282 uses a HY12P65 chipset that has UART capability , on datasheet pin 20 or TX/PT1.4
http://www.hycontek.com/wp-content/uploads/DS-HY12P65-EN.pdf (http://www.hycontek.com/wp-content/uploads/DS-HY12P65-EN.pdf)

i probed the pin but nothing comes out of it, so i though that maybe the serial tx was disabled, i managed to dump the eeprom from the multimeter , ic was atmel 24C08N
http://ww1.microchip.com/downloads/en/devicedoc/atmel-8787-seeprom-at24c04c-08c-datasheet.pdf (http://ww1.microchip.com/downloads/en/devicedoc/atmel-8787-seeprom-at24c04c-08c-datasheet.pdf)

i'll attach the eeprom bin file and maybe also the dump from another similam multimeter the hy_19E beacuse they  are the same multimeter.

so is there anyone that can guide me to modify the eeprom to enable the tx pin?

any help is really appreciated, keep in mind that i'm a noob when it comes to eeprom reading and understanding


NOTES

idont know the name of the chip on the left

i soldered 2 cables on the left header because i tought i found the serial out .. so i was trying to read that with a serial to usb converter. i obtained only trash from the serial monitor . i'm not really sure what signal is that but its coming from the ht12p65 pin PT2.2/PWM/PFD pin 14 .. in the datasheet its written as pwm port or PFD PORT (wtf is that?)
i think its a signal that the 2 ic uses to communicate but i have no clue

in the rar there are 2 bins the zeast282 is the one that i dumped , the hy19e bin was taken from a russian site

again what is a PFD PORT??

signal in the next post
Title: Re: Multimeter EEPROM modding Zeast282 RX/TX enabling
Post by: Atom on September 17, 2019, 05:20:59 pm
so this is the signal on pin 14 the ?PFD OUTPUT? i dont know what this is but i tought i should share it anyways, the times in red are in microseconds. the signal i think is coming from the hy12p65 ang going into the other chip and then to the header... soo any ideas of what that could be?

if you have any question feel free to ask