ETMv3 Trace Port Mode

The Port speed:ETM clock speed ratio enables the trace port to run at a different speed from that of the core. The list of options is limited to those appropriate for the ETM:

  • Dynamic (for use with on-chip trace buffers). This is the only available option if you are using ETB 11.

  • 1:1 (the port speed is the same as the ETM clock speed).

  • 1:2 (the port speed is half the ETM clock speed).

  • 1:3 (the port speed is one third of the ETM clock speed).

  • 1:4 (the port speed is one quarter of the ETM clock speed).

  • 2:1 (the port speed is double the ETM clock speed).

  • Implementation defined (defined by the ASIC manufacturer).

image\inform.gif   The Port speed:ETM clock speed ratio defines the rate of the trace port, not the trace clock speed. The trace clock speed is always half the trace port rate, because half-rate clocking is always enabled for ETMv3.

Half-rate clocking enabled

This setting is mandatory for ETMv3. It is selected automatically and grayed out.
image\openred.gif  See the ETM control register section of the ARM Embedded Trace Macrocell Specification.

Disabled traceport  

Select this option if you want to suppress the output from the trace port. Use this to control trace output if your hardware has two or more ETMs sharing a single trace port.