Products > Test Equipment
Uni-T UT139c LCD biasing and other mods
dimkasta:
I just did this to my two UTs using an old Arduino pro I had around (duemilanove generation). The pinout is the same as in the Uno (same chip)
I confirm that the boards need good voltage and good connections for the communication to work properly.
I thought I could do this using just a header stuck in the holes, but it would just not work.
It finally worked when I pushed the header sideways, forcing it to have a better connection with the programming holes.
I also noticed that it was easier to get a reading when the PW, GND and VCC where close together. Probably because there was less voltage loss in comparison to using the long ground traces on the other side of the board.
Finally, on my second DMM, I could not get a non-ticking connection. I kept moving things around, but no solid connection. But then the sketch started reporting the memory dump and programmed the changes while the main chip was ticking.
I guess we only need a solid connection with the eeprom. The functionality of the main chip is irrelevant, and if I had to guess, it is probably because of low voltage reaching it through the thin wires/traces.
By the way, the lcd mod was virtually worthless. The main problem is the useful viewing angle of the lcd. Even at 3.3V it looks pretty crappy looking it up front.
It would be cool if we could find a replacement :)
Here's a photo of my wiring
Kbird:
Mine only "ticked" or chirped constantly when it was wired incorrectly I found but I'm not sure which wire it was now... V- to ground perhaps?
SCL and SDA should be the same pinout physically as you say , and I can even with my DMM test they are connected , so I am unsure
why the broken out pins didn't work , unless it is something to do with the sketch programming or that I'm using a Clone not an Official Leo / Uno.
KB.
Nitec0re:
Hello
My 139C does come next week and I would like to flash the DDM. But I have no skills with the Arduino Board and I dont understand the Code.
Is there someone who can edit the code from #18 for copy/paste for me (bought a original Arduino Uno only for this)? I need two Versions of the Code.
First: ONLY eeprom dump for saving and Backup
Second: A Code for reflash the DMM with 3.3V for the Display, 15min Auto-Off and NO auto-off for the Backlight
Why two separate Codes? Because its much easier for me to handle 8)
Kbird:
My modified Sketch in No#18 only reads the Eeprom and Dumps the eeprom to the Serial Monitor window on the 1st run, which you then copy and paste to Notepad, and save as your default Eeprom as a Backup. You then need to modify the sketch and uncomment ( // ...delete this) from the 2nd section,reupload the sketch and it will program the eeprom All the instructions are actually in the Sketch if you read through it....I am no expert , so I tried to make it understandable for Newbies like me and you.
you could simply make two copies of the Sketch , one commented ( no edits) and the other altered and uncommented as needed.
you do need a SOIC Clip or be able to add pins to the PCB to do this as I did.....I soldered mine in and left them for further use.
Nitec0re:
Thank you for the reply.
For the first run I leave the code as it is. And for the second run I have to remove the // in line:
105 for the 3.3V
113 for the extendPowerOn
115 for the Backlight
and I have to change the hex value in line 199 and 205 from 0x1e to 0x0 for manual controlled Backlight and no auto power off - right?
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version