User guide

Trace Port Interface Unit
ARM DDI 0337I Copyright © 2005-2008, 2010 ARM Limited. All rights reserved. 11-4
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11.2.3 Serial Wire Output format
The TPIU can output trace data in a Serial Wire Output (SWO) format:
• TPIU_DEVID specifies the formats that are supported. See TPIU_DEVID on page 11-12.
• TPIU_SPPR specifies the SWO format in use. See the ARMv7-M Architecture Reference
Manual.
When one of the two SWO modes is selected, you can enable the TPIU to bypass the formatter
for trace output. If the formatter is bypassed, only the ITM and DWT trace source passes
through. The TPIU accepts and discards data from the ETM. This function can be used to
connect a device containing an ETM to a trace capture device that is only able to capture SWO
data.