MC68HC11PH8 Datasheet, PDF (59/264 Pages) Motorola, Inc – High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcomputer Unit

PH8.DS03/Modes+mem
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FREEZ — Address bus freeze in expanded user mode
1 (set) – The external bus is only active when externally mapped resources
2
are accessed (expanded mode only).
0 (clear) – Normal operation.
To reduce RFI emissions, the address bus (on ports B and F) is not active while internal resources
3
are being accessed, but will instead freeze on the last external address. At this time, the data bus
port C is three-stated (high impedance) with weak pull-ups active, R/W is forced high and the E
clock enable is pulled low. At reset, the address bus is initialized to $FFFE. Refer to Figure 3-2.
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Internal E
IMMP
(internal
signal)
E
ADDR
Internal
5
External
Internal
6
7
DATA
(Resistive pull-up)
In
Out
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R/W
9
Figure 3-2 Example of expanded mode FREEZ actions
CLK4X — 4X clock enable
1 (set) – 4XCLK or EXTALi driven out on the 4XOUT pin (see Section 3.3.2.5)
0 (clear) – 4XOUT pin disabled.
Note: The 4XOUT pin is not available on 84-pin packaged devices.
PAREN — Pull-up assignment register enable (refer to Section 4)
1 (set) – Pull-ups can be enabled using PPAR.
0 (clear) – All pull-ups disabled (not controlled by PPAR).
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MC68HC11PH8
OPERATING MODES AND ON-CHIP MEMORY
¬^TPG
MOTOROLA
3-13
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