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External Signals
MOTOROLA
MPC823 USER’S MANUAL
2-5
EXTERNAL
SIGNALS
2
CS7
CE2_B
B15
Chip Select 7—This output signal enables a peripheral or memory device at a
programmed address if defined appropriately in the BR7 and OR7 registers of the
memory controller.
Card Enable 2 Slot B—This output signal enables odd byte transfers when
accesses to the PCMCIA Slot B are handled by the PCMCIA interface.
WE0
BS_AB0
IORD
D16
Write Enable 0—This output signal is asserted when a write access to an external
slave controlled by the GPCM in the memory controller is initiated by the MPC823.
WE0 is asserted if the data lane D[0:7] contains valid data to be stored by the slave
device.
Byte Select 0 on UPMA or UPMB—This output signal is asserted as required by the
UPMA or UPMB in the memory controller whenever you program it. In a read or write
transfer, the signal is only asserted if the data lane D[0:7] contains valid data.
I/O Device Read—This output signal is asserted when the MPC823 initiates a read
access to a region controlled by the PCMCIA interface. The signal is only asserted if
the access is to a PC Card I/O space.
WE1
BS_AB1
IOWR
E16
Write Enable 1—This output signal is asserted when the MPC823 initiates a write
access to an external slave controlled by the GPCM in the memory controller. WE1
is asserted if the data lane D[8:15] contains valid data to be stored by the slave
device.
Byte Select 1 on UPMA or UPMB—This output signal is asserted as required by the
UPMA or UPMB in the memory controller whenever you program it. In a read or write
transfer, the signal is only asserted if the data lane D[8:15] contains valid data.
I/O Device Write—This output signal is asserted when the MPC823 initiates a write
access to a region controlled by the PCMCIA interface. The signal is only asserted if
the access is to a PC Card I/O space.
WE2
BS_AB2
PCOE
D15
Write Enable 2—This output signal is asserted when the MPC823 initiates a write
access to an external slave controlled by the GPCM in the memory controller. WE2
is asserted if the data lane D[16:23] contains valid data to be stored by the slave
device.
Byte Select 2 on UPMA or UPMB—This output signal is asserted as required by the
UPMA or UPMB in the memory controller whenever you program it. In a read or write
transfer, the signal is only asserted if the data lane D[16:23] contains valid data.
PCMCIA Output Enable—This output signal is asserted when the MPC823 initiates
a read access to a memory region under the control of the PCMCIA interface.
WE3
BS_AB3
PCWE
F13
Write Enable 3—This output signal is asserted when the MPC823 initiates a write
access to an external slave controlled by the GPCM in the memory controller. WE3
is asserted if the data lane D[24:31] contains valid data to be stored by the slave
device.
Byte Select 3 on UPMA or UPMB—This output signal is asserted as required by the
UPMA or UPMB in the memory controller whenever you program it. In a read or write
transfer, the signal is only asserted if the data lane D[24:31] contains valid data.
PCMCIA Write Enable—This output signal is asserted when the MPC823 initiates a
write access to a memory region controlled by the PCMCIA interface.
GPL_A0
GPL_B0
E13
General-Purpose Line 0 on UPMA—This output signal reflects the value specified
in the UPMA in the memory controller when an external transfer to a slave is
controlled by the user programmable machine A (UPMA).
General-Purpose Line 0 on UPMB—This output signal reflects the value specified
in the UPMB in the memory controller when an external transfer to a slave is
controlled by the user programmable machine B (UPMB).
GPL_A1
GPL_B1
OE
C16
General-Purpose Line 1 on UPMA—This output signal reflects the value specified
in the UPMA in the memory controller when an external transfer to a slave is
controlled by the user programmable machine A (UPMA).
General-Purpose Line 1 on UPMB—This output signal reflects the value specified
in the UPMB in the memory controller when an external transfer to a slave is
controlled by the user programmable machine B (UPMB).
Output Enable—This output signal is asserted when the MPC823 initiates a read
access to an external slave controlled by the GPCM in the memory controller.
Table 2-1. Signal Descriptions (Continued)
SIGNAL
PIN NUMBER
DESCRIPTION