HD6433832S Datasheet, PDF (74/560 Pages) Renesas Technology Corp – single-chip microcomputers

As a result of this operation, bit 0 in PCR3 becomes 0, making P3₀ an input port. However, bits 7
and 6 in PCR3 change to 1, so that P3₇ and P3₆ change from input pins to output pins.
To avoid this problem, store a copy of the PCR3 data in a work area in memory. Perform the bit
manipulation on the data in the work area, then write this data to PCR3.
[A: Prior to executing BCLR]
MOV. B
MOV. B
MOV. B
#3F,
R0L,
R0L,
R0L
@RAM0
@PCR3
The PCR3 value (H'3F) is written to a work area in memory
(RAM0) as well as to PCR3.
Input/output
Pin state
PCR3
PDR3
RAM0
P3₇
Input
Low
level
0
1
0
P3₆
Input
High
level
0
0
0
P3₅
Output
Low
level
1
0
1
P3₄
Output
Low
level
1
0
1
P3₃
Output
Low
level
1
0
1
P3₂
Output
Low
level
1
0
1
P3₁
Output
Low
level
1
0
1
P3₀
Output
Low
level
1
0
1
[B: BCLR instruction executed]
BCLR #0 , @RAM0
[C: After executing BCLR]
MOV. B @RAM0, R0L
MOV. B R0L, @PCR3
The BCLR instruction is executed designating the PCR3
work area (RAM0).
The work area (RAM0) value is written to PCR3.
Input/output
Pin state
PCR3
PDR3
RAM0
P3₇
Input
Low
level
0
1
0
P3₆
Input
High
level
0
0
0
P3₅
Output
Low
level
1
0
1
P3₄
Output
Low
level
1
0
1
P3₃
Output
Low
level
1
0
1
P3₂
Output
Low
level
1
0
1
P3₁
Output
Low
level
1
0
1
P3₀
Output
High
level
0
0
0
Table 2.12 lists registers that share the same address, and table 2.13 lists registers that contain
write-only bits.
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