There is one last thing I want to do before I leave my AN8008 alone.
There is some missing functionality button-wise:
RANGE - There already is a range button but it doesn't work as it should, I want a separate button.
MIN/MAX - That's very useful to have.
REL - This is necessary to turn on serial communication. I've already set eeprom address 0xFA to value 0xCE to allow that.
I will need to make a few holes to add these buttons as well as one for the comm. wires (I don't want infrared leds) but I've already figured out the best way to do that on the meter case thanks to our friends in the various Russian forums.
Now, this is were I get confused and need your help.
This is the diagram I use to understand how the DMM processor is connected to the pcb:
https://media.licdn.com/mpr/mpr/AAIA_wDGAAAAAQAAAAAAAAqmAAAAJDA3Nzc5MDhiLTliZjMtNGY0Zi05OTcwLWExZjY2ZjU4YTczYg.jpgQuestions:
- I notice how the buttons are connected to the processor and I come to the conclusion that if for example I want to let the processor know that MIN/MAX was pressed all I have to do is to temporarily connect PIN 23 (PT1.1) to PIN 26 (PT3.7). Is it that simple or is there something else I'm missing?
- I can see that PIN 20 is my TX PIN which I can use to send data to my PC. But I can also see that PIN 21 is an RX PIN. Do I need that?
- Finally, is there anyone who knows where the PTx.x PINS that have to do with the aforementioned buttons are located on the 8008 PCB? Since this is a COB chip, I reckon it's a bit of a guessing game to locate the pins you are interested in. I will also need to locate the TX PIN.
This button issue is confusing to me because for example on the top right of the PCB there are contacts for a button (I think it's supposed to be a RANGE button?) and all it does is nothing (connects PT1.1 to BATT-). Why do they have contacts for a button that seems to do nothing? Is there something I'm missing with the whole button setup?
I have also watched this video:
It's a Russian guy who mods a ZT102 (AN8002) meter to add buttons. The points on the PCB he marks on his video to get specific button functionality, don't do anything on my AN8008 but work fine on his meter. This confuses me even more!
I would appreciate any response to help clarify these things.