T1022NXE7MQA
| Model | T1022NXE7MQA |
| Description | 32-BIT, 1200MHz, RISC PROCESSOR, PBGA780 |
| PDF file | Total 197 pages (File size: 1M) |
| Chip Manufacturer | PHILIPS |
Hardware design considerations
Boundary-scan testing is enabled through the JTAG interface signals. The TRST_B
signal is optional in the IEEE Std 1149.1 specification, but it is provided on all processors
built on Power Architecture technology. The device requires TRST_B to be asserted
during power-on reset flow to ensure that the JTAG boundary logic does not interfere
with normal chip operation. While the TAP controller can be forced to the reset state
using only the TCK and TMS signals, generally systems assert TRST_B during the
power-on reset flow. Simply tying TRST_B to PORESET_B is not practical because the
JTAG interface is also used for accessing the common on-chip processor (COP), which
implements the debug interface to the chip.
The COP function of these processors allow a remote computer system (typically, a PC
with dedicated hardware and debugging software) to access and control the internal
operations of the processor. The COP interface connects primarily through the JTAG port
of the processor, with some additional status monitoring signals. The COP port requires
the ability to independently assert PORESET_B or TRST_B in order to fully control the
processor. If the target system has independent reset sources, such as voltage monitors,
watchdog timers, power supply failures, or push-button switches, then the COP reset
signals must be merged into these signals with logic.
The arrangement shown in
allows the COP port to independently assert
PORESET_B or TRST_B, while ensuring that the target can drive PORESET_B as well.
The COP interface has a standard header, shown in
for connection to the target
system, and is based on the 0.025" square-post, 0.100" centered header assembly (often
called a Berg header). The connector typically has pin 14 removed as a connector key.
The COP header adds many benefits such as breakpoints, watchpoints, register and
memory examination/modification, and other standard debugger features. An inexpensive
option can be to leave the COP header unpopulated until needed.
There is no standardized way to number the COP header; so emulator vendors have
issued many different pin numbering schemes. Some COP headers are numbered top-to-
bottom then left-to-right, while others use left-to-right then top-to-bottom. Still others
number the pins counter-clockwise from pin 1 (as with an IC). Regardless of the
numbering scheme, the signal placement recommended in
is common to all
known emulators.
4.5.1.1
Termination of unused signals
If the JTAG interface and COP header will not be used, Freescale recommends the
following connections:
• TRST_B should be tied to PORESET_B through a 0 kΩ isolation resistor so that it is
asserted when the system reset signal (PORESET_B) is asserted, ensuring that the
QorIQ T1042, T1022 Data Sheet, Rev. 2, 06/2015
Freescale Semiconductor, Inc.
177
