EPE MagLogger problems

Dear friends

some issues re the EPE mag logger:

I recently built a new unit (the original was broken...) and I have the following problems:

* the pic does not recognize either of the installed eeprom chips (message "0 eeprom chips"), even when only one chip is installed
* when the eepprom erasing function is invoked ('Null' + 'On' switches), the software shows that chip 1 and 2 are being 'cleared' but then continues with 'chip 3' (?!) and so on (probably, because no eepprom's were found)
* although the 'Record' function seems to work, no data are written to either of the eeproms
* no data are transferred to PC upon activation of the relevant function

The circuitry as well as all connections to switches seem to be ok; 5V is established where necessary, while all components were checked and seem not to be faulty.

The PIC (16F877-20) has been initially programmed with both Microchip's Pickit3 and Velleman's K8076 programmers; it was then re-programmed with the same devices, but without improvement with respect to the above behaviour.

One other thing to be noticed is that after some programming sessions, the PIC program was not working at all, showing only the message 'EPE Magnetometer, 0 eeprom chips'  but no other function whatsoever; while, after some other programming sessions it functioned like the descriptions in the beggining of the post.

Finally, I tested the same PIC on two similar PCB's, and the overall behaviour is exactly the same on both boards (some times a faulty function, some other times no function at all).

Is this a problem of the PIC, of the programming, or of the board circuitry?

Any help would be much appreciated as well as any tips regarding the testing of the circuit.

TXs
lazzy




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GD

I'm using the HEX code and the board design provided by EPE, however the board itself was made locally by a professional board manufacturer.

I agree that there may be 'openings' in the track desing, leading to such intermittent and 'peculiar' problems. But I also feel that there might be some shortcomings in the original track/or component design, making the constuction generally 'unstable'.

I will follow your tips.

regards
lazzy


Posted on: June 11, 2014, 08:37:59 am

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GD

Am I allowed to post the circuit (not the board) design for the named EPE device, as appears from the original PDF file (Fig.1), so that you can have an idea about the pin connections?

regards
lazzy

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http://www.thunting.com/smf/index.php/topic,56987.msg276039.html#msg276039

I have not a way to check the internal pull-up res of the pic - I just have the hex/asm files provided by epe mag.

However: following a tip from a member of another forum, I put a 10K resistor between IC6 out and IC4 pin#1; with that, I succeeded in having both eeproms detected (most of the time, at least...)

But, still, when transferring data to a PC, I only get empty files or files with less data than those corresponding to the downloaded memory bits, while sometimes no connection can be established.

I will try to put a resistor between the pic's pin#40 and data pin of TB1 (as you suggested in an older post)

regards
lazzy

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Attached is the mag diagram.

Well, my programmer (PicProg2009) does not allow such adjustments.

I resoldered all pcb connections and all switches, etc. I then reprogrammed 4 pics with the same programmer: eeprom chips (1 or 2, if both are installed) are now correctly seen (and erased, when needed); all other functions seem ok and smooth, but no data transfer is possible whatsoever (same for all pics) ; sometimes, transfer is done, but received data are nonsense or simply an empty file.

I changed the eeprom chips and the other IC's, but the faulty results persist, for every pic.

Any suggestion as to how to proceed would be much appreciated.

regards
lazzy

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