GPIB-to-USB interface with Arduino Nano UPDATE

I discovered that the memory in the Arduino Nano gets corrupted when leaving the GPIB-to-USB interface connected to an active GPIB bus while it is no longer powered by the USB connection. This video shows how I solved this problem, first temporary using a switch and then by enabling Brown-Out Detection (BOD) on the ATmega328p (or 328pb).
Since I am using a clone Arduino Nano in this interface, it turned out to be using an ATmega328pb which has a different signature (1E9516) from the standard 328p (1E950F). This causes some problems when burning fuse bytes or uploading the bootloader but the video shows a solution for that.
The 1st Solartron restauration video: • Solartron 7150+ bench-...
The original GPIB interface video: • Solartron 7150+ part 2...

[@jafinch78]

Just found this checking back in again before I start the next GPIB interface project. Excellent to read about you finding out a solution. Thanks for sharing!

[@cad3175]

..wow that's great problem solving on display, fantastic!

[@konohh]

Thanks for all the great videos. As I am right now in the need of a simple USB to GPIB Adapter, this is exactly what I was looking for. This project saves me tons of money and is a fabulous way to put at least one of those arduino pcbs to a good use. BTW, the link on your Github page to Rudis Wiki results in a 404 error.

[@TheHWcave]

Nice to hear. You are absolutely right if you have already an Arduino all you need is a handful resistors, a cable and the GPIB connector. Can't beat that for price. Thanks for the note on the broken link. I managed to find it again and updated the Github page. Rudi must have reorganised his stuff.

[@t1d100]

Clever solution.

[@radio655]

Wow, interesting. Who would have thought.

[@ManchesterBlackSheep]

Thanks for this. When you say the GPIB interface chips are really expensive, I assume you do not mean the physical level chips, because they are pennies. The value comes, surely, in the micro side of things that implements the protocol? Unfortunately, the 75160 & 75161 chips which make the physical interface robust are now going obsolete. 😔 I don't like the idea of hooking a micro directly to the bus though.

[@TheHWcave]

I agree that hanging a bus directly on a microprocessor output is not ideal. As you said, the 7516x chips are getting obsolete and expensive. I looked prices up just now out of curiosity. About £4 for 20 in RS, no smaller quantities which would make this £80 for one (with 19 spares). I did not check other vendors. Even if I can buy just one for say £6 somewhere, I'd call that expensive (for my budget...) . Of note, I have since modified my build to github.com/Twilight-Logic/AR488 which uses 7516x chips. I thought I made a video about it but it turns out I never did. I highly recommend it, the firmware is way more capable than what I used before and I have used it for more than a year on a bus with 6 instruments (and growing)

[@ManchesterBlackSheep]

@@TheHWcave We're looking at slightly higher volume than one or two here (and on a very expensive piece of kit), so the price in slightly higher voumes is fine for us. 🙂 I think it's a really big problem that these chips are going obsolete. From what I understand GPIB isn't going away (despite it being insanely old and innnapropriate in the age of high speed serial comms). I would not be surprised if a smaller company licensed the chips or made their own as I'm sure the demand will continue for some time.

[@nicolasjonasson4820]

Would this work for other multimeters? Got two HP 34401A

[@TheHWcave]

It should but I have not tried it. It does use addressing in the commands, so theoretically it can talk to 2 or more devices on the same bus. The big question is whether it will work hardware-wise and what kind of cables and termination are needed. You see, I copied that design from some guy (with permission). It is not my design and I have not looked at GPIB ever since, and as long as it works with my Solatron I am happy and the interface is now permanently attached to the rear of the Solartron. If, for whatever reason the multi-device mode is not working or the cost of special plumbing (cables) is too much, the cost of an additional Arduino Nano isn't the world, so its possible to use two, each handling a simple single-ended GPIB connection to a dedicated 34401A while on the other end - all USB connections - end in a USB hub that is connected to your PC. I do have a 34401A myself but for reasons outlined above I use the serial port to talk SCPI over a serial-to-USB interface. Being able to use the 34401A remotely is incredibly useful so I fully understand your desire to get this working, especially if you have 2. Another thing to consider is that you will have to write your own PC software (or at least wrappers) for the Arduino GPIB interface but there is at least some software out there that uses SCPI over serial ports (I think SIGROK supports SCPI over serial, but I don't use it myself).

[@nicolasjonasson4820]

@@TheHWcave I'm super thankful for the time you took, writing this reply! Much info here. I got two GPIB-cables, the thickness/stiffness of them is almost bizarre :) Maybe serial is the way to go though...I will look into it. Again, thanks for the shared knowledge.

[@TheHWcave]

@@nicolasjonasson4820 No problem. One hint. Get a reasonable USB-to-Serial adaptor that implements DTR/DSR. Many cheap ones do not. Sadly the 34401 uses (only) DTR/DSR and not RTS/CTS which is far more common in serial interface adaptors. If you can't get the serial interface to work, it is most likely a DTR/DSR issue.

[@2LukeLOL]

Good solution! But can't you just disable BOD by writing to the MCUCR register?

[@TheHWcave]

No idea. You know more about that than I. My projects use mainly Raspberry Pi and only occasionally will I stray into Arduino land. It would be great if a simple register setting could solve this. I will have a look for future projects but not change the current adapter.

[@2LukeLOL]

@@TheHWcave ah I see! I just had a check on the datasheet. So you can disable brown out detection using software IF you put the microcontroller into deep sleep mode. Unfortunately, you cannot keep the brown out detection off while it is running so it wouldn't work. Looks like burning the fuses is the only solution to this problem!

[@TheHWcave]

@@2LukeLOL Thanks for checking it.

[@jimexotech8631]

Are you from Germany ?

[@TheHWcave]

Hi Jerome, yes, born there but left many years ago ...