ARM Cortex-M3 User Manual

Trace Port Interface Unit
17-14 Copyright © 2005-2008 ARM Limited. All rights reserved. ARM DDI 0337G
Bit [8] of this register is always set to indicate that triggers are indicated when
TRIGGER is asserted.
When one of the two single wire output modes is selected, bit [1] of this register enables
the formatter to be bypassed. If the formatter is bypassed, only the ITM/DWT trace
source (ATDATA2) passes through. The TPIU accepts and discards data that is
presented on the ETM port (ATDATA1). This function is intended to be used when it is
necessary to connect a device containing an ETM to a trace capture device that is only
able to capture Serial Wire Output data. Enabling or disabling the formatter causes
momentary data corruption.
Note
If the selected pin protocol register is set to 0x00 (TracePort mode), the Formatter and
Flush Control Register always reads
0x102 , because the formatter is automatically
enabled. If one of the serial wire modes is then selected, the register reverts to its
previously programmed value.
Formatter Synchronization Counter Register
The global synchronization trigger is generated by the Program Counter (PC) Sampler
block. This means that there is no synchronization counter in the TPIU.
The register address, access type, and Reset state are:
Address
0xE0040308
Access Read only
Reset state
0x00
[3:2] - Reserved.
[1] EnFCont Continuous Formatting, no TRACECTL. This bit is set on reset.
[0] EnFTC Enable Formatting. Because TRACECTL is never present, this bit reads as zero.
Table 17-9 Formatter and Flush Control Register bit assignments (continued)
Bits Field Function

ARM Cortex-M3 Specifications

General

Architecture	ARMv7-M
Instruction Set	Thumb-2
Pipeline Stages	3-stage
Interrupts	Nested Vectored Interrupt Controller (NVIC)
Interrupt Controller	Nested Vectored Interrupt Controller (NVIC)
Memory Protection Unit	Optional
Power Consumption	Varies by implementation
Max Clock Speed	Up to 100 MHz
Debugging	JTAG and Serial Wire Debug (SWD)
Operating Voltage	1.8V to 3.6V
Manufacturing Process	Varies by implementation
Core Type	32-bit