NEC V850E/RS1 User Manual page 125

(2) Registers
(a) Port register 3 (P3)
Port register 3 (P3) is a 16-bit register used to control pin level read and output level write.
This register can be read and written in16-bit, 8-bit and 1-bit units.
However, when using the higher 8 bits of the P3 register as the P3H register and the lower 8 bits
as the P3L register, P3 becomes two 8-bit registers for which I/O can be manipulated in 8-bit or
1-bit units.
Symbol
P3H
R/W
Symbol
P3L
R/W
Remarks: 1. Input mode:
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Chapter 4 Port Functions
Figure 4-20: Port Register 3 (P3) Format
15 14 13 12
0 0 0 0
R/W R/W R/W R/W
7 6 5 4
P37 P36 P35 P34
R/W R/W R/W R/W
P3n Output data control (in output mode) (n = 0 to 9)
0 Outputs 0
1 Outputs 1
When port 3 (P3) is read, the pin levels at this time are read. During
write, the data written to P3 is written. This does not affect the input
pins.
Output mode: When port 3 (P3) is read, the value of P3 is read. During write, the
value is written to P3 and the written value is immediately output.
2. An undefined value (pin input level) is read for the value after reset when P3 is read in
the input mode. When P3 is read in the output mode, 00H (output latch value) is output.
User's Manual U16702EE3V2UD00
11 10 9
0 0 0 P38
R/W R/W R/W R/W
3 2 1
P33 P32 P31 P30
R/W R/W R/W R/W
8 Address After reset
FFFFF407H undefined
0 Address After reset
FFFFF406H undefined
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