Public Version
www.ti.com
SDTI Module
27.3.5 SDTI Basic Programming Model
27.3.5.1 Trace Setup
To enable trace, perform the following steps:
1. If setup is performed through application software, enable write access to the SDTI by writing unlock
key to the lock access register (
).
2. Claim the SDTI through the ownership procedure.
3. Configure the serial interface.
4. Configure
to enable message generation.
5. Enable the SDTI through the ownership procedure.
Interface configuration (data width, serial clock selection, dual-/single-edge of operation) must be
considered as static and are not to be changed on the fly. The serial interface must be properly configured
before enabling trace capture and the interface configuration must not be changed while data are in the
SDTI FIFO.
If the address window is disabled (CPU1 and CPU2 message generation is disabled in the
register while data are in the SDTI FIFO), the serial interface continues to export data
until the FIFO is drained.
Write access to the disabled address window has no effect.
If SDTI ownership is released while data are in the SDTI FIFO, the serial interface continues to export
data until the FIFO is drained.
If released (in AVAILABLE ownership state), the SDTI does not generate new messages.
If one trace session ends and a new session starts without a change in the interface configuration, the
programming model is:
1. Disable trace.
2. Wait until SDTI FIFO is drained.
3. Enable trace and thus start a new session.
This ensures that the first message in the new session is always exported with the address field.
In case of a short disable/enable sequence (when trace is re-enabled while data from a previous session
are still in the SDTI FIFO), session breaks are filtered out (disregarded). From an address compression
standpoint, when compression is on, the message address field in the new session depends on the
previous trace session.
Functional or message generation mode has priority over serial interface test mode (if message
generation and test mode are enabled, the SDTI is in functional mode).
27.3.5.2 Serial Interface Test Mode Setup
To enable serial interface test mode, perform the following steps:
1. If setup is performed through application software, enable write access to the SDTI by writing unlock
key to the lock access register (
).
2. Claim the SDTI through the ownership procedure.
3. Configure the serial interface.
4. Configure
to disable message generation.
5. Configure
to select test pattern and test pattern generation mode.
6. Enable the SDTI through the ownership procedure.
The SDTI continues to export test patterns until one of the following occurs:
•
Serial test mode is disabled.
•
Message generation is enabled.
•
The SDTI is released.
3619
SWPU177N – December 2009 – Revised November 2010
Debug and Emulation
Copyright © 2009–2010, Texas Instruments Incorporated