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Thread: M847 extended edition > Bootloader in PDP style !

  1. #41
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    Follow up on Roland's "Extended M847" -

    The board had a rough trip here – it got from the Netherlands to Chicago in two days but then spent more than two weeks languishing in the USPS ISC (International “Service” Center) before being sent on to me (I live less than an hour from the ISC). No indication of why it was held up – it wasn’t opened or inspected. Regardless, it arrived here in perfect condition but only just before the Thanksgiving (US) holiday weekend, so even then it was put aside for a bit.

    I finally got to it last night and was very pleased to find that it performs exactly as described in Roland’s YouTube demo. At first, I was a little concerned about keying in all the selection codes but it actually works quite easily. After loading a few tests using the SW lever from the front panel, I switched to the Select button on the actual board and found it very easy to use. The “human engineering” is done quite well – the board gives just the right amount of time to enter the select codes, with a brief pause after startup and then it generates a halt and reloads the next test if selected. It also puts out a quick front panel “scanner” pattern on power up to let you know it’s there and thus provides a quick confidence test.

    The board I received had the version 1. 0 code uploaded to the Atmega328. I tried to upgrade it to v 1.1 in place, using the BC01V connector on the board but I was unsuccessful – the Arduino IDE recognized the board but the upload failed with a security error. I’ll wait for more info from Roland on this; in the short term, I just removed the chip and installed it in an Arduino, reprogrammed it and then reinstalled it on the board. Not a big deal.

    Really a nice job and a helpful addition to my PDP8 toolkit – thanks Roland!

  2. #42

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    Hi Jack,

    Thanks for the review!

    Good to hear the board arrived and works in you machine! For uploading the program trough
    the BC01V you need to power up the PDP8. RS232 can't power the board.

    If someone builds a new board with a complete blank chip, you need to take the
    PCB out of the PDP and connect a Arduino Uno as ISP and connect the board like this:
    https://raw.githubusercontent.com/Ro...bootloader.jpg
    In this way you can flash the Arduino bootloader and the Arduino uno is powering the M847 then.
    (So it's easier to buy a pre programmed chip from ebay and skip this part...)

    When the Arduino bootloader is already in the board you can upload the M847 firmware
    trough the Arduino IDE with the BC01V of DB9 cable. The board then needs to be
    in de PDP8 and you have to power-up the PDP.

    These are the test programs 20 and above. (35 and 36 still need to be put in the software)
    https://github.com/Roland-Huisman/M8...in%20tests.pdf
    You need this info to use those tests.

    Does anyone know who wrote these tests? I want to put in the credits to the writer.

    Regards, Roland
    Last edited by Roland Huisman; December 2nd, 2018 at 12:05 AM.
    WTB: Case for Altair 8800 ...... Rolands Github projects

  3. #43
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    Just got my PCB fabs back today from JLPCB, built from Roland's v1.1 gerbers. ENIG finish with red soldermask, gold fingers with 45deg finish mill.

    pcb.jpg

    I had 10 pcs built, I'm only going to need a couple or three at most, so the rest are available. $10 each incl basic shipping to US addresses. More for special shipping. PM me if interested.

    Don

  4. #44
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    Don,
    Boards look really good, .......PM sent

    Harry

  5. #45
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    Quote Originally Posted by AK6DN View Post
    Just got my PCB fabs back today from JLPCB, built from Roland's v1.1 gerbers. ENIG finish with red soldermask, gold fingers with 45deg finish mill.

    pcb.jpg

    I had 10 pcs built, I'm only going to need a couple or three at most, so the rest are available. $10 each incl basic shipping to US addresses. More for special shipping. PM me if interested.

    Don
    Ok, all the 10 boards are spoken for. That was faster than I thought (less than 2hrs). Guess I should have bought a larger quantity.

    FYI, going to JLPCB website, uploading .zip'ed gerber file, and choosing options was pretty easy. For users in Europe or Australia (where shipping from US is lots of $$) probably a better option to go to JLPCB and get boards fabbed (in blocks of 10) and shipped to you directly, and then sell some to your local buddies ...

    Don

  6. #46
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    Don,

    When you say "gold fingers", does that mean hard gold on the fingers as opposed to the ENIG finish on the rest of the board? Seems like a great price, especially if that is the case.

  7. #47
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    I have a couple of boards going through JLPCB at the moment and asked exactly the same question.

    No, the gold on the fingers is not hard gold.

    I decided in the end to go with them despite this - the cost was prohibitively high for a hard gold finish from other suppliers.

    Dave

  8. #48
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    Quote Originally Posted by daver2 View Post
    I have a couple of boards going through JLPCB at the moment and asked exactly the same question.

    No, the gold on the fingers is not hard gold.

    I decided in the end to go with them despite this - the cost was prohibitively high for a hard gold finish from other suppliers.

    Dave
    Dave is correct; the board is all ENIG plated (~5u Au over ~200u Ni) as opposed to hard gold (30u Au over 100u Ni) on the fingers.

    So the boards are not going to survive lots of insertion/removal events without some damage to the fingers.

    But as Dave indicated hard gold is a high cost option (if it is even available, not all vendors will do it) these days.

    But for the US$5.55 cost per board (incl shipping from China to California) that is about all you can expect.

  9. #49

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    A little update for the component list which I will put in the Github files as well...
    The advice is to buy the ATMEGA328P-PU (picopower version) and not the ATMEGA328-PU.

    A little background: You can use both the ATMEGA328-PU and ATMEGA328P-PU in
    the board when they have the Arduino bootloader in it already.

    If you bought blank ATMEGA328-PU chips, you have to do a little trick to load that bootloader in the chip.
    I have both model chips running and I was not aware of this difference because the non
    pico power version had the bootloader in it already. So thanks to Matthew Greer for mentioning this!

    But to be honest, I would buy the pre loaded ATMEGA328P-PU version anyway...

    Regards, Roland
    WTB: Case for Altair 8800 ...... Rolands Github projects

  10. #50
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    Funny, I helped a member at our local makerspace programming his atmega 328 boards (audio synthesizer modules) yesterday, and we hit the same obstacle. I solved it in a different way, googled how to write the bootloader via the command line, and then just adding '-F' to the avrdude command line.
    This article was the one we used as a reference.
    And I never thought about looking deeper into that signature difference.
    Last edited by tingo; December 22nd, 2018 at 12:20 PM. Reason: expanded a bit
    Torfinn

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