Yet Another USB GPIB Interface (yaugi)

[essele]

Ok ... a new day, a new cable ... a working device!



I used some self-amalgamating tape to get some strain relief, seems to work really well.

The bootloader is also done and working, so now you can update the firmware without needing a Cypress programmer.

I've run out of PSoC's (I'm also using them on a USB BME280 based temp/humidy/pressure sensor) as I've got three on the go in prototypes. I've ordered a batch of ten which should allow me to build out the adapters I need, plus a couple that I can ship for help with testing.

I'll get the GitHub updated with the new PCB and the bootloader stuff over the next few days.

[trobbins]

Adding some vias and backside pads in or around the usb cabling pads may make resoldering to the pads a bit more robust.  You'd have to move the pcb text.

[essele]

I think I've settled on this approach ...



It solves the cable attachment problem, uses a through hole usb connector (which is also clamped in by the connector strain relief clamp), and overall is a lot less fiddly to put together ... takes about 30mins or so. Plus you now have your choice of cables/lengths to use.

I do need to respin it once more as the pcb width going through the cable outlet was slightly too wide, not helped by the round rather than oval holes on the usb connector footprint, so it needed a little filing.

So ... cost breakdown:

PCB	JLCPCB	£ 1.70
MCU	CY8C4246AZI-L433	£ 5.90
Programming Header	2x5 1.27mm AliExpress	£ 0.07
GPIB Connector	(Aliexpress)	£ 1.96
USB Connector	651005136521	£ 1.00
Fuse	MF-MSMF050-2	£ 0.42
Diode	MBR0520L	£ 0.18
Caps (3)	2x1uF, 1x0.1uF	£ 0.06

I've allowed £1 for the USB connector, I'm using ones that came in a AliExpress "selection" which clearly will be much less than this, the footprint I've used is the 651005136521, but you don't seem to be able to buy that anywhere that I can find.

The PCB's cost a total of £8.50 for a batch of 5 the vast majority of which is shipping costs, so £1.70 each -- clearly this reduces if you order more. If you only want one, then clearly you're going to have to pay for a batch.

All costs are either what I paid or current Farnell or Mouser costs and include UK VAT, I didn't particularly look for cheap fuses or diodes, I just used the ones that were used in one of the dev boards.

So that's a grand total of £11.29 ... so not quite under £10, but not far off ... and a far cry from anything else you could buy (and a lot more compact!)

[maginnovision]

Looks good.   

[niner_007]

I’m not a big fan of the enclosure

[Bud]

GPIB is dead because it is so awfully slow, except for reading old DVMs and frequency counters.

Last year i attended a Keysight seminar where they had latest greatest gear that still had GPIB. I asked if Keysight is going to sunset GPIB. "Hell NO!"  was the answer.

[maginnovision]

I’m not a big fan of the enclosure

I think you can make a few nice changes(preferably different enclosure and hardwired cable) by just putting in some extra cash. If you wanted a cheap barebones way to do usb-gpib this will work though.

[essele]

I’m not a big fan of the enclosure

I think you can make a few nice changes(preferably different enclosure and hardwired cable) by just putting in some extra cash. If you wanted a cheap barebones way to do usb-gpib this will work though.

Wow ... tough crowd!   

I'm not particularly mad on the enclosure either, but 24-Way Centronics connectors don't seem to be that popular any more so there's not a great choice, and I don't have a 3D printer (yet) to do something myself. If anyone can find something better, I'm quite happy to rework the board as needed.

Also ... these are going to be tucked away at the back of an instrument ... is it that important?

I do get that a hardwired cable is an option some people might prefer (I thought I was in that camp, but I think I've changed my mind) so both are options, in fact the original board with right angled PCB mount connector is also still an option, all three are fundamentally the same and use the same firmware. I have some of the hardwired cable PCB's if anyone wants one at cost (plus shipping), and I've got a batch of the new ones coming. (PM me if interested.)

Also, I'll put all board details on the GitHub once I've made sure the new one is correct.

As a side note .. I was reworking my USB code for an environmental sensor module yesterday and discovered that you can configure multiple "devices" in the USB config in the PSoC and then switch at runtime, so I'll add a config option to switch between UART and TMC, that's much nicer than having to have different firmware. Also looking at programatically returning the device and manufacturer strings, so you should be able to set them in the config and make it easier to figure out which device is which if you have a few.

[maginnovision]

For me the hardwired cable is mostly about strain. It's a little awkward to be hanging a cable from that, also the extra distance it'd stick out. That could be fixed with a right angle USB cable though. I actually don't have a better enclosure in mind so I'd probably end up measuring to see what works, design it, and send it out to be made. I actually think it's good to have the "budget" version though. Honestly, if you have firmware that's open source and ready to go people can work around that however they'd like. The design you're doing could be the reference design.

[essele]

Yes, fair points.

I'm not sure the extra distance is too much of an issue, once you take into account the bend radius of the power lead, it's not really adding anything to the overall depth.



(Assuming you're not using right angled power leads of course ... which bizarrely I am!)

[artag]

This is why I arranged the cable to come out of the side on the design I did : https://www.eevblog.com/forum/projects/ar488-arduino-based-gpib-adapter/msg2718346/#msg2718346

(admittedly, as you can see from the attached stacking connector, it was the wrong side. I'm addressing that.)

[lordium]

This reminds me of something I made back when I needed this (which I still use today). Works with all equipment I've tested with (HP, R&S, TR from all ages).
STM32, and USB connector can mount both top and bot for pulling cable left or right. Still have the code and kicad if anyone's interested.

EDIT: added 7zip files, also noticed last code was old version, added new one ported to STM32CubeIDE

[giovannirat]

Still have the code and kicad if anyone's interested.

Would be great if you could share it....

Thanks

[Zinahe]

Just wondering if there is any update on this project. I'm very interested. I've got a few old instruments that need some lovin'.

Cheers,

[essele]

Hi Zinahe,

I've been working quietly (and slowly!) on this in the background as my needs change.

I've now put the focus on flexibility rather than GPIB transfer performance and I now have a bit of a framework that I can use for a variety of different devices that are built on the same basic PSoC MPU with USB.

1. The Yaugi GPIB adapter
2. A BME280 based temperature sensor
3. A USB based switch unit

So the framework supports customisable commands and configs, supports saving configs to flash, supports dynamic switching between USBUART and USBTMC, and re-flashing using the PSoC host based firmware utility.

On the GPIB side I've reworked the UART interface and moved away from Prologix compatibility in order to be a bit more prescriptive about whether a given command should expect a response or not which makes it easier to code a standard API for it.

There's still a lot more to do but I'm really doing other things, so I'm only working on it as my needs dictate, over the weekend I got it working with my shiny new(*) 3458a, so I'm doing some data gathering at the moment and probably won't get back to working on the code for a week or so.

(*) New -- as in new to me ... it's nearly 30 years old!

[essele]

Just a heads-up as I've just got it powered up for the first time, but I've now pulled together a PoE (802.3af) version...



It's using a W5500 attached to the PSoC, and an amazing tiny PoE module from Silvertel (less than $10 qty 1!!)

https://www.silvertel.com/images/datasheets/Ag9900M-datasheet-ultra-miniature-isolated-Power-over-Ethernet-POE-module.pdf

I haven't written any of the ethernet code yet, I've just checked that power is ok and that I have connectivity from the PSoC to the W5500. I've forgotten the bloody serial port, which will make debugging a little more painful although I may just bodge something in.

I also think I'm breaking all the rules about isolation, but that should be just a board rework challenge once it's all up and running.