Atmel ICE/PowerDebugger TPI issues on MacOS

[mcuee]

From the comments here.

• Added TPI support for Microchip tools #1205 (comment)

@MCUdude mentioned the following.

I have no idea what's causing the Atmel ICE/PowerDebugger TPI issues on MacOS, but that's out of scope for this PR. It may be libusb-related, but it's really weird. But the fact that I'm having the exact same issues when using the Atmel ICE/Power Debugger with MPLAB X on MacOS tells me that someone at Microchip may be aware of this problem.

I believe just like avrude, MPLAB X under Linux and macOS will also hidapi or libusb to talk to the Microchip tools. In paticular to macOS and Atmel ICE, only hidapi can be used and not libusb. Under Windows, I believe MPLAB X uses Windows native HID API (for HID devices) or WinUSB API (nfor on HID generic USB devices).

So this could be an hidapi problem, or Atmel ICE/Power Debugger FW issue. Since there is no issue under Linux, I tend to think this is more like a Atmel ICE/Power Debugger FW issue.

Even though this does not seem to be an avrdude issue, maybe there is a workaround for macOS user. I will try to contact Microchip Singapoe to see if I can get a hold of Atmel ICE to carry out the test. This may take some time though.

[mcuee]

Move this to discussion as this may well be a firmware issue and not avrdude issue.

[mcuee]

Wiki updated and I will close this one.
https://github.com/avrdudes/avrdude/wiki/Known-limitations-of-avrdude#known-issues-for-programmers