MC68HC912DG128 Datasheet, PDF (99/452 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Bus Control and Input/Output
Registers
BIT 7
6
5
4
3
2
PE7
PE6
PE5
PE4
PE3
PE2
RESET:
—
—
—
—
—
—
Alt. Pin
Function
DBE or
ECLK or
CAL
MODB or
IPIPE1 or
CGMTST
MODA or
IPIPE0
ECLK
LSTRB or
TAGLO
R/W
PORTE — Port E Register
1
BIT 0
PE1
PE0
—
—
IRQ
XIRQ
$0008
This register is associated with external bus control signals and interrupt
inputs, including data bus enable (DBE), mode select (MODB/IPIPE1,
MODA/IPIPE0), E clock, size (LSTRB), read/write (R/W), IRQ, and
XIRQ. When the associated pin is not used for one of these specific
functions, the pin can be used as general-purpose I/O. The port E
assignment register (PEAR) selects the function of each pin. DDRE
determines the primary direction of each port E pin when configured to
be general-purpose I/O.
Some of these pins have software selectable pull-ups (DBE, LSTRB,
R/W, IRQ, and XIRQ). A single control bit enables the pull-ups for all
these pins which are configured as inputs.
This register is not in the map in peripheral mode or expanded modes
when the EME bit is set.
Read and write anytime.
MC68HC912DG128 — Rev 3.0
MOTOROLA
Bus Control and Input/Output
For More Information On This Product,
Go to: www.freescale.com
Technical Data
99