Intel 8XC196MC User Manual page 511

8XC196MC, MD, MH USER'S MANUAL
Px_REG
P x _REG
x = 2–5 (8XC196MC)
x = 2–5, 7 (8XC196MD)
x = 1–5 (8XC196MH)
For an input, set the corresponding port x data output (P x _REG) register bit.
For an output, write the data to be driven out by each pin to the corresponding bit of P x _REG. When a
pin is configured as standard I/O (P x _MODE. y = 0), the result of a CPU write to P x _REG is
immediately visible on the pin. When a pin is configured as a special-function signal (P x _MODE. y = 1),
the associated on-chip peripheral or off-chip component controls the pin. The CPU can still write to
P x _REG, but the pin is unaffected until it is switched back to its standard I/O function.
This feature allows software to configure a pin as standard I/O (clear P x _MODE. y ), initialize or
overwrite the pin value, then configure the pin as a special-function signal (set P x _MODE. y ). In this
way, initialization, fault recovery, exception handling, etc., can be done without changing the operation
of the associated peripheral.
7
x = 1 (MH)
7
x = 2–5 (M x ) PIN7
7
x = 7 (MD) PIN7
Bit
Bit Number
Mnemonic
†
7:0 PIN7:0
†
The bits shown as dashes (—) are reserved; for compatibility with future devices, write zeros to
these bits.
Table C-10. P x _REG Addresses and Reset Values
Register
P1_REG (8XC196MH)
P2_REG (8XC196M x )
P3_REG (8XC196M x )
P4_REG (8XC196M x )
P5_REG (8XC196MC, MD)
P5_REG (8XC196MH)
P7_REG (8XC196MD)
C-34
— — —
PIN6 PIN5
PIN6 PIN5
Port x Pin y Output
To use P x . y for output, write the desired output data to this bit. To use
P x . y for input, set this bit.
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— PIN3 PIN2
PIN4 PIN3 PIN2
PIN4 PIN3 PIN2
Function
Address Reset Value
1F9DH FFH
1FD4H FFH
1FFCH FFH
1FFDH FFH
1FF5H FFH when pin is not driven
1FF5H FFH
1FD5H FFH
Address: Table C-10
Reset State:
PIN1 PIN0
PIN1 PIN0
PIN1 PIN0
0
0
0