MPC7441 datasheet(41/56 Pages) NXP

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MPC7447A RISC Microprocessor Hardware Specifications, Rev. 5

Freescale Semiconductor

System Design Information

The COP header shown in Figure 19 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). The connector typically has

pin 14 removed as a connector key.

There is no standardized way to number the COP header shown in Figure 19; 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 19 is common to all known emulators.

The QACK signal shown in Figure 19 is usually connected to the PCI bridge chip in a system and is an

input to the MPC7447A informing it that it can go into the quiescent state. Under normal operation this

occurs during a low-power mode selection. In order for COP to work, the MPC7447A must see this signal

asserted (pulled down). While shown on the COP header, not all emulator products drive this signal. If the

product does not, a pull-down resistor can be populated to assert this signal. Additionally, some emulator

products implement open-drain type outputs and can only drive QACK asserted; for these tools, a pull-up

resistor can be implemented to ensure this signal is negated when it is not being driven by the tool. Note

that the pull-up and pull-down resistors on the QACK signal are mutually exclusive and it is never

necessary to populate both in a system. To preserve correct power-down operation, QACK should be

merged through logic so that it also can be driven by the PCI bridge.

MPC7441 数据表(PDF) 41 Page - NXP Semiconductors