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Topic: GPIBUSB Adapter rev3 (Read 33815 times) previous topic - next topic

Re: GPIBUSB Adapter rev3

Reply #15
Hey everyone, got another update for this project to share.

After working closely with a few individuals it was discovered that some of the pre-existing GPIB software (such as KE5FX's tools) has some hardcoded serial port settings, one of which being the use of hardware flow control. After getting builds of the software tools with these disabled, some buffer problems were found using the default settings, under Windows, without the flow control. Running the software with WINE on Linux did not produce these issues. With some small tweaks to either the software or to Windows USB settings would fix the issue but that's not very intuitive. A better long term solution would be to wire up the hardware flow control lines in the next hardware revision for use in a future firmware update.

That's what I've done with the revision 4 PCB. In addition, I grounded a few unused digital lines on the micro to be able to, starting with rev4+, check what the hardware revision is in software. I also added two LEDs to the FT230X to allow it to signal on TX and RX.


Re: GPIBUSB Adapter rev3

Reply #16
Does anyone know of a design for a GPIB to USB converter? (I know that is what this is called, but it is really a USB to GPIB converter which are plentiful, but, as noted, expensive.) I want a GPIB to USB converter so that I can use a conventional USB printer with a GPIB instrument such as a spectrum analyzer, logic analyzer, etc. Years ago, you could buy inkjet and laserjet printers that had IEEE-488 interfaces to use with such instruments, but today those printers are almost impossible to find. So, something that went from GPIB to USB would be very useful for allowing people with IEEE-488 test equipment to use modern USB printers.
I've looked, but so far I have not found any such products or designs.
Ed

 

Re: GPIBUSB Adapter rev3

Reply #17
I tried to build something like this myself, so I figured I could use the code, but I don't have the non-free compiler that was used to build it. So I started translating it to SDCC, which gave me some funny warnings about unreachable code. And then I realised that these are in fact bugs. Binary "OR" is not the same as logical "OR".