13.1.3. TPIU inputs and outputs

This section describes the TPIU inputs and outputs. It contains the following:

Trace out port

Table 13.1 describes the trace out port signals.

Table 13.1. Trace out port signals

NameTypeDescription
TRACECLKINInputDecoupled clock from ATB to enable easy control of the trace port speed. Typically this is derived from a controllable clock source on chip, but an external clock generator could drive it if a high speed pin is used. Data changes on the rising edge only.
TRESETnInputThis is a reset signal for the TRACECLKIN domain. This signal is typically driven from Power on Reset, and must be synchronized to TRACECLKIN.
TRACECLKOutputTRACEDATA changes on both edges of TRACECLK.
TRACEDATA[3:0]OutputOutput data for clocked modes.
TRACESWOOutputOutput data for asynchronous modes.

ATB interface

There is one or two ATB interfaces depending on the TPIU configuration. Table 13.2 describes the ATB port signals. The signals for port 2 are not used when the TPIU is configured with a single ATB interface.

Table 13.2. ATB port signals

NameTypeDescription
CLKInputTrace bus and APB interface clock.
nRESETInputReset for the CLK domain (ATB/APB interface).
CLKENInputClock enable for CLK domain.
ATVALID1SInputData from trace source 1 is valid in this cycle.
ATREADY1SOutputIf this signal is asserted (ATVALID high), then the data was accepted this cycle from trace source 1.
ATDATA1S[7:0]InputTrace data input from source 1.
ATID1S[6:0]InputTrace source ID for source 1. This must not change dynamically.
ATVALID2SInputData from trace source 2 is valid in this cycle.
ATREADY2OutputIf this signal is asserted (ATVALID high), then the data was accepted this cycle from trace source 2.
ATDATA2S[7:0]InputTrace data input from source 2.
ATID2S[6:0]InputTrace source ID for source 2. This must not change dynamically.

Miscellaneous configuration inputs

Table 13.3 describes the miscellaneous configuration inputs.

Table 13.3. Miscellaneous configuration inputs

NameTypeDescription
MAXPORTSIZE[1:0]InputDefines the maximum number of pins available for synchronous trace output.
SyncReqInputGlobal trace synchronization trigger. Inserts synchronization packets into the formatted data stream. Only used when the formatter is active. This signal must be connected to the DSYNC output from Cortex-M3.
TRIGGERInputCauses a trigger packet to be inserted into the trace stream when the formatter is active.
SWOACTIVEOutputSWO mode selected (use for pin muxing).
TPIUACTIVOutputIndicates that the TPIU has data which is in the process of being output.
TPIUBAUDOutputToggles at baud frequency (in TRACECLKIN domain).
Copyright © 2005, 2006 ARM Limited. All rights reserved.ARM DDI 0337E
Non-Confidential