MPC8313E datasheet(84/92 Pages) FREESCALE

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MPC8313E PowerQUICC™ II Pro Processor Hardware Specifications, Rev. 1

Freescale Semiconductor

System Design Information

is also used for accessing the common on-chip processor (COP) function, simply tying TRST to

PORESET is not practical.

The COP function of these processors allows 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 TRST without causing

PORESET. 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 Figure 46 allows the COP to independently assert HRESET or TRST, while

ensuring that the target can drive HRESET as well. If the JTAG interface and COP header are not used,

TRST should be tied to PORESET so that it is asserted when the system reset signal (PORESET) is

asserted.

The COP header shown in Figure 46 adds many benefits—breakpoints, watchpoints, register and memory

examination/modification, and other standard debugger features are possible through this interface—and

can be as inexpensive as an unpopulated footprint for a header to be added when needed.

The COP interface has a standard header for connection to the target system, based on the 0.025"

square-post, 0.100" centered header assembly (often called a Berg header).

There is no standardized way to number the COP header shown in Figure 46; consequently, many different

pin numbers have been observed from emulator vendors. Some are numbered top-to-bottom then

left-to-right, while others use left-to-right then top-to-bottom, while still others number the pins counter

clockwise from pin 1 (as with an IC). Regardless of the numbering, the signal placement recommended in

Figure 46 is common to all known emulators.

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