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LPC1764 Assistance

Discussion in 'ARM' started by Micro9900, Jul 16, 2013.

  1. Micro9900

    Micro9900 New Member

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    Hey guys, I made a post on LPCware.com, but their forum isn't the best (takes forever to get a response and to get a post through since it must go through moderation each time).

    Here is the link to the post:

    LINK

    I made the following response (which at this time is still in the process of being posted...):

    So, if anyone has any experience with the LPC1764, LPC expresso, or has an idea as to how to fix this it would help a lot. Thanks.
     
  2. DirtyLude

    DirtyLude Well-Known Member

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    I'll try, but most of this will be speculation. I've only used full JTAG with the LPC17xx, but I've used SWD with the LPC11xx and 13xx. Where did you get that schematic from, because the SWD connections are wrong? Pin one should be VDD, but instead its got a resistor going to TRST. Pin 10 should be nRESET. TRST is a JTAG pin and should be pulled up, 10k.
     
  3. Micro9900

    Micro9900 New Member

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    The connections I have for SWD are as follows:

    LPC1768 Pin # <------> LPC-Link 2 Pin #
    __________________________________
    (SWDIO) 3 <------> 2 (SWDIO)
    (SWCLK) 5 <------> 3 (SWCLK)
    (RESET) 17 <------> 6 (RESET)
    All VDD <------> 1 (3v3)
    All GND <------> 8 (GND)

    *In between all VDD and GND I have a 100nF capacitor

    Thank you for the repy, I placed a 10k pullup on pin 4 (TRST of LPC1768). I believe the rest of my connections are correct (they're different from above schematic) as it was working before. If you see anything else out of place though please let me know. I think the one thing that is missing from the schematic is a 10K pullup resistor on pin 53 (p2.10) for ISP pin.

    I keep switching between the two errors mentions above. One method was ISP pin fix (hold pin low upon startup), another was setting vector cache to true, and the last was programming via UART to unbrick the microcontroller.

    I'm going to try the UART fix and see if it works. So far, I don't like how cumbersome ARM is compared to PIC32. I really never ran into this issue once I had the proper hardware and software with PIC32, which is why I am a bit confused at this point.

    EDIT:
    _________

    I am having difficulty with flash magic. It keeps giving me an "autobaud rate" error. I looked into it a bit and it could be the connections. The way I have it connected it as follows:

    LPC1768 Pin # <------> FTDI RS232 3v3 Pin #
    __________________________________
    All VSS <------> 1 (GND)
    All VDD <------> 3 (Power)
    (RXD1) 74 <------> 4 (TXO)
    (TXD1) 75 <------> 5 (RXT)

    I have made to select the right part (LPC1764) and I have imported the hex file that was taken from the build of interest using LPC Expresso.

    EDIT2:

    I made my own schematic in attempts to clear up any confusion with my connections.

    [​IMG]
     
    Last edited: Jul 19, 2013
  4. dave

    Dave New Member

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  5. Micro9900

    Micro9900 New Member

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    Got it working. It was a soldering/ pin issue. Also, quick note. In the above schematic I accidentally connected RESET to pin 7 and not 6. It was correct in the circuit I was troubleshooting, but incorrect in the above schematic (just in case anyone wants to use it).
     

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