C-33
REGISTERS
Px_REG
P
x
_REG
x
= 1–4
Address:
Reset State:
Table C-14
For an input, set the corresponding port x data ouput (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
0
x
= 1–3
PIN7
PIN6
PIN5
PIN4
PIN3
PIN2
PIN1
PIN0
7
0
x
= 4
—
—
—
—
PIN3
PIN2
PIN1
PIN0
Bit Number
Bit
Mnemonic
Function
7:0
PIN7:0
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.
Table C-14. P
x_REG Addresses and Reset Values
Register
Address
Reset Value
P1_REG
1FD4H
FFH
P2_REG
1FD5H
FFH
P3_REG
1FDCH
FFH
P4_REG
1FDDH
FFH
Содержание 80C196NU
Страница 1: ...8XC196NP 80C196NU Microcontroller User s Manual...
Страница 2: ...8XC196NP 80C196NU Microcontroller User s Manual August 1995 Order Number 272479 002...
Страница 18: ...1 Guide to This Manual...
Страница 19: ......
Страница 31: ......
Страница 32: ...2 Architectural Overview...
Страница 33: ......
Страница 48: ...3 Advanced Math Features...
Страница 49: ......
Страница 56: ...4 Programming Considerations...
Страница 57: ......
Страница 72: ...5 Memory Partitions...
Страница 73: ......
Страница 106: ...6 Standard and PTS Interrupts...
Страница 107: ......
Страница 144: ...7 I O Ports...
Страница 145: ......
Страница 165: ......
Страница 166: ...8 Serial I O SIO Port...
Страница 167: ......
Страница 183: ......
Страница 184: ...9 Pulse width Modulator...
Страница 185: ......
Страница 196: ...10 Event Processor Array EPA...
Страница 197: ......
Страница 225: ......
Страница 226: ...11 Minimum Hardware Considerations...
Страница 227: ......
Страница 239: ......
Страница 240: ...12 Special Operating Modes...
Страница 241: ......
Страница 255: ......
Страница 256: ...13 Interfacing with External Memory...
Страница 257: ......
Страница 303: ......
Страница 304: ...A Instruction Set Reference...
Страница 305: ......
Страница 373: ......
Страница 374: ...B Signal Descriptions...
Страница 375: ......
Страница 390: ...C Registers...
Страница 391: ......
Страница 447: ......
Страница 448: ...Glossary...
Страница 449: ......
Страница 458: ...Index...
Страница 459: ......