Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

isolation for Altera programmer

I have a situation where the ground of my FPGA circuit is at a potential a few volts below the earth ground. Normally, if my FPGA and PC grounds are the same, I use a USB Blaster to program either th...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

Thank you for the responses. Full speed seems to be the one that most of the USB isolators work with, so that is welcome news.

If I were only using the port for JTAG purposes, I would be more inclined to build in isolators. The ones you suggest look like good choices. However, since I will also be using the port with a USB Blaster to load data into the EPCS device, this gets a bit more complicated. During that process, the USB Blaster apparently tri-states some of the signals and there is no access to the tri-state control signals. With more knowledge of the EPCS writing protocol, isolation of it might be possible too but isolating at the USB level seems to be easier. (especially now that I know the USB Blaster uses Full speed)