System Design Information
mutually exclusive and it is never necessary to populate both in a system. To preserve correct power-down operation,
QACK should be merged via logic so that it also can be driven by the PCI bridge.
SRESET
From Target
Board Sources
(if any)
SRESET
HRESET
HRESET
QACK
10 kΩ
10 kΩ
10 kΩ
10 kΩ
HRESET
13
11
OV
DD
SRESET
OV
OV
DD
DD
DD
OV
5
0 Ω
TRST
1
3
2
4
6
8
TRST
4
6
VDD_SENSE
OV
OV
DD
10 kΩ
2 kΩ
5
1
5
DD
7
CHKSTP_OUT
CHKSTP_OUT
15
10 kΩ
9
10
OV
OV
DD
DD
Key
14
11
12
10 kΩ
2
KEY
No Pin
13
15
CHKSTP_IN
TMS
CHKSTP_IN
TMS
8
9
1
3
16
COP Connector
Physical Pin Out
TDO
TDI
TDO
TDI
TCK
7
2
TCK
QACK
QACK
10
NC
NC
3
2 kΩ
OV
DD
12
16
4
10 kΩ
Notes:
1. RUN/STOP, normally found on pin 5 of the COP header, is not implemented on the MPC7455. Con
pin 5 of the COP header to OV with a 10-kΩ pull-up resistor.
DD
2. Key location; pin 14 is not physically present on the COP header.
3. Component not populated. Populate only if debug tool does not drive QACK.
4. Populate only if debug tool uses an open-drain type output and does not actively de-assert QACK
5. If the JTAG interface is implemented, connect HRESET from the target source to TRST from the
header though an AND gate to TRST of the part. If the JTAG interface is not implemented, con
HRESET from the target source to TRST of the part through a 0-Ω isolation reisistor.
Figure 26. JTAG Interface Connection
MPC7455 RISC Microprocessor Hardware Specifications, Rev. 4.1
Freescale Semiconductor
53
FREESCALE [ Freescale ]
