HD64F3644PV Datasheet, PDF (78/551 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 2 CPU
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 #3F, R0L
MOV. B R0L, @RAM0
MOV. B R0L, @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
The BCLR instruction is executed designating the PCR3
work area (RAM0).
[C: After executing BCLR]
MOV. B @RAM0, R0L
MOV. B R0L, @PCR3
Input/output
Pin state
PCR3
PDR3
RAM0
P37
Input
Low
level
0
1
0
P36
Input
High
level
0
0
0
The work area (RAM0) value is written to PCR3.
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
Rev. 6.00 Sep 12, 2006 page 56 of 526
REJ09B0326-0600