M68HC16 Z SERIES
REGISTER SUMMARY
USER’S MANUAL
D-9
POW — Power-Up Reset
Reset caused by the power-up reset circuit.
SW — Software Watchdog Reset
Reset caused by the software watchdog circuit.
HLT — Halt Monitor Reset
Reset caused by the halt monitor.
SYS — System Reset
The CPU16 does not support this function. This bit will never be set.
TST — Test Submodule Reset
Reset caused by the test submodule. Used during factory test reserved operating
mode only.
D.2.5 System Integration Test Register E
SIMTRE — System Integration Test Register E
$YFFA08
Used for factory test only.
D.2.6 Port E Data Register
This register can be accessed in two locations and can be read or written at any time.
A write to this register is stored in an internal data latch, and if any pin in the corre-
sponding port is configured as an output, the value stored for that bit is driven out on
the pin. A read of this data register returns the value at the pin only if the pin is config-
ured as a discrete input. Otherwise, the value read is the value stored in the register.
Bits [15:8] are unimplemented and will always read zero.
D.2.7 Port E Data Direction Register
Bits in this register control the direction of the port E pin drivers when pins are config-
ured for I/O. Setting a bit configures the corresponding pin as an output; clearing a bit
configures the corresponding pin as an input. This register can be read or written at
any time. Bits [15:8] are unimplemented and will always read zero.
PORTE0 — Port E0 Data Register
$YFFA10
PORTE1 — Port E1 Data Register
$YFFA12
15
8
7
6
5
4
3
2
1
0
NOT USED
PE7
PE6
PE5
PE4
PE3
PE2
PE1
PE0
RESET:
U
U
U
U
U
U
U
U
DDRE — Port E Data Direction Register
$YFFA14
15
8
7
6
5
4
3
2
1
0
NOT USED
DDE7
DDE6
DDE5
DDE4
DDE3
DDE2
DDE1
DDE0
RESET:
0
0
0
0
0
0
0
0
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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