November 24, 2024, 04:32:39 PM

ARM-USB-TINY-H and SWO / Trace in SWD mode

Started by kladha, September 09, 2014, 04:49:34 PM

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kladha

Has anyone managed to successfully get the ARM-USB-TINY-H to output the trace / SWO line to a com port?

The hardware looks like it is possible:
Crossworks -> ARM-USB-TINY-H -> ARM-JTAG-SWD -> ARM-JTAG-20-10
The schematic shows SWO -> TDO_CC for the adapter
The scope shows it working ok

However:
Windows does not create any virtual com ports for the ARM-USB-TINY-H
Various driver combinations have been tried
Device manager shows no extra COM ports
Corssworks asks for a COM port number to route the trace from

Any help would be very useful

JohnS

I don't see why you think it would be via a COM port.  I think it would not be.

Best ask the Crrossworks people.

John

roboknight

As was mentioned, that's *NOT* going to come from a com port.  The setup you have basically routes the ARM 10 pin JTAG to  20 pins, then, in this case, takes the signaling from SWD to standard ARM JTAG.

Are you sure the Trace you are looking at from CrossWorks is the SAME trace as SWO?  Because the SWO is a method for supplying the old 38 or so pin trace hardware functionality via a single pin and wouldn't be provided on a serial port.  CrossWorks would need to decode anything coming from SWO to give you the trace, and it would get that from the ARM TDO pin.  The SWD standards provide for this functionality to a standard 20 pin JTag.

http://www.google.com/imgres?imgurl=http://www.support.code-red-tech.com/CodeRedWiki/HardwareDebugConnections%253Faction%253DAttachFile%2526do%253Dget%2526target%253D20pin.png&imgrefurl=http://www.support.code-red-tech.com/CodeRedWiki/HardwareDebugConnections&h=248&w=250&tbnid=KOGPdkw6hv9sUM:&zoom=1&docid=-_KzP02yCcoNtM&ei=QAA6VLZtituwBKGEgTg&tbm=isch

The CrossWorks trace sounds more like an "output terminal".