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Proto Board Rev A - No Propeller chip found on any serial port — Parallax Forums

Proto Board Rev A - No Propeller chip found on any serial port

MacTuxLinMacTuxLin Posts: 821
edited 2011-09-11 00:48 in Propeller 1
I wired up a protoboard to act as one of our tester for one of our board after its assembly. It worked fine for quite a while until today. After testing & swapping with other proto-boards to eliminate other accessories as the root cause, I'm still back to square one.

This thing is, this protoboard (tester) still functions as normal (power-up, load from EEPROM, etc..) but when I connect the prop plug to it, I did not receive any debug info from PST which I should. So I tried from Propeller Tool, after pressing F7, it said "No Propeller ..". But the reset seems to work as the protoboard restarted every time I press F7. I did not use pin 30 & 31 in the testing of the assembled boards. I only use pin 0,1,2,13,15,16,19.

The function of the proto-board (tester) is:
1. Sends a binary code to our assembled board's RAM
2. Assembled board then runs the test & sends the result back to tester
3. Tester then blink either PASS or FAIL (LED)

Any suggestion to test as to why this protoboard is not talking to me?

Thanks.

Comments

  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2011-09-09 07:34
    MacTuxLin,

    Can you provide a close-up photo of your board and schematics? if you don't want to post the schematics, you can E-mail them to me at bschwabe@parallax.com ... any code that you are trying to load might be helpful as well.

    Have you checked the obvious? Sometimes they are easy to overlook. i.e. Proper power to the board, Propeller Plug not backwards, etc.
  • Mike GreenMike Green Posts: 23,101
    edited 2011-09-09 07:40
    Have you tried a different PropPlug? It sounds like the reset and ground connections are working from the PropPlug to the Propeller, but there's a problem with the data connection from the Propeller to the PC. Focus on what happened between when the Protoboard seemed to work properly and when it failed.
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2011-09-09 08:19
    MacTuxLin,

    Which Proto board do you have? ...If the prop plug is in backwards and you try to program the Propeller, it will reset and fail to programming it.
  • MacTuxLinMacTuxLin Posts: 821
    edited 2011-09-09 09:00
    Beau Schwabe (Parallax) wrote: »
    MacTuxLin,

    Can you provide a close-up photo of your board and schematics? if you don't want to post the schematics, you can E-mail them to me at bschwabe@parallax.com ... any code that you are trying to load might be helpful as well.

    Have you checked the obvious? Sometimes they are easy to overlook. i.e. Proper power to the board, Propeller Plug not backwards, etc.

    Thanks Beau. I'm back home now so I only have an old pic of the board in my phone. The only difference with the current board is that I've added another yellow LED to show when the test starts as these are very helpful to the operation team working on the boards.

    As for the obvious, I've tested:
    1. Using other Proto-board (I have only 2 spares left) with the same power-in adaptor. Other Proto-board could be detected but not this one. I even tried other power adaptors but results are the same.

    2. As for prop plugs, I have 3. I've tested all on 3 different PC and all other Proto-boards can be detected except for this one. As for backward, erm... I usually check the "Vss" against the board's headers so I doubt its wrong as I could still see the ground pin's connection to the ground plane on the Proto-board & ... I even used a multimeter to test if the prop plug's headers are in contact with the propeller's pin 30, 31, reset & ground. They are OK.

    The final resort is to just do up another Proto-board for this test as I got to get it ready before Monday.
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  • MacTuxLinMacTuxLin Posts: 821
    edited 2011-09-09 09:07
    Mike Green wrote: »
    Have you tried a different PropPlug? It sounds like the reset and ground connections are working from the PropPlug to the Propeller, but there's a problem with the data connection from the Propeller to the PC. Focus on what happened between when the Protoboard seemed to work properly and when it failed.

    Thanks Mike. Yes, I've done that but its only this board that failed to be detected. Other Proto-boards worked fine with these 3 Prop Plugs ...

    The thing is, once I've finished with this tester, the people assembling the boards used this tester to test the boards. It was working OK until when 1 board failed. So when I wanted to connect to the PST to check the read outs, the PC could not detect it.
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2011-09-09 09:46
    What is the voltage on the power supply? The 5V regulator should have at least 1.2V overhead making the input voltage requirement at least 6.2V Seems I have run into a similar problem as you describe, only because I skimmed and used a 5V supply where I should have used one slightly higher. In some cases the 5V supply worked just fine and I could program a Propeller without any problems, but in other cases the Propeller wouldn't program at all. The 'fix' was to provide an adequate power supply.
  • MacTuxLinMacTuxLin Posts: 821
    edited 2011-09-09 09:48
    Beau Schwabe (Parallax) wrote: »
    What is the voltage on the power supply? The 5V regulator should have at least 1.2V overhead making the input voltage requirement at least 6.2V Seems I have run into a similar problem as you describe, only because I skimmed and used a 5V supply where I should have used one slightly higher. In some cases the 5V supply worked just fine and I could program a Propeller without any problems, but in other cases the Propeller wouldn't program at all. The 'fix' was to provide an adequate power supply.

    All our boards uses a 12V 1A power adaptor.
  • LeonLeon Posts: 7,620
    edited 2011-09-09 10:09
    It looks as though you have a hardware problem with that particular board. Check the connections on the Propeller chip leads and the board connectivity.
  • MacTuxLinMacTuxLin Posts: 821
    edited 2011-09-09 10:12
    Leon wrote: »
    It looks as though you have a hardware problem with that particular board. Check the connections on the Propeller chip leads and the board connectivity.

    Hmm...didn't occur to me that could be at fault but why not. I only went so far as to test the PropPlug's headers & the thru-hole pads of 30,31... OK, I'll test tomorrow when I'm in office. Thanks Leon.
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2011-09-09 10:15
    12V might be too much... at 12V that 5V regulator needs to drop 7V ... and if you are pulling 200mA from both Propellers and other things, that's 1.4Watts of wasted energy in the form of heat the regulator needs to dissipate.

    That said, the regulator might be fine, but worth checking... What I'm looking at is the red wire (see attached) that appears to be going to the 'daughter' Propeller board. The other end of the red wire is connected to Vin, which by what you have said is 12V. Is that the intention? If so, then I don't see a regulator on the 'daughter' Propeller board to bring the voltage down for the Propeller... Just what looks like a big diode (1-2Amp by the looks of it)
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  • MacTuxLinMacTuxLin Posts: 821
    edited 2011-09-09 10:22
    Beau Schwabe (Parallax) wrote: »
    12V might be too much... at 12V that 5V regulator needs to drop 7V ... and if you are pulling 200mA from both Propellers and other things, that's 1.4Watts of wasted energy in the form of heat the regulator needs to dissipate.

    That said, the regulator might be fine, but worth checking... What I'm looking at is the red wire (see attached) that appears to be going to the 'daughter' Propeller board. The other end of the red wire is connected to Vin, which by what you have said is 12V. Is that the intention? If so, then I don't see a regulator on the 'daughter' Propeller board to bring the voltage down for the Propeller... Just what looks like a big diode (1-2Amp by the looks of it)

    Thanks Beau. Yes, apart from this board, we use the same adaptors for other boards that connects to multiple servos, so..

    Yes, on the daughter board, there is a LD1117 underneath together with 24LC512. Yes, its a 1N5404. I think I'm gonna crash ... I'll check again tomorrow morning. Thanks again ..
  • MacTuxLinMacTuxLin Posts: 821
    edited 2011-09-11 00:48
    I've tested the Proto-board's leads, they are connected to the PropPlug headers.

    Someone, in a PM, advice me about the bypass caps on Proto-board. Did't realized they are all missing on the Proto-board so I've placed 4 x 0.1uF on each Vss/Vdd but that didn't help either.

    I gave up. I'll temporarily do up a breadboard tester using my Prop1 Module before designing a proper tester for this model.
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