
deveopmen
Rev.B2 for proof reading
Timer A
Mitsubishi Microcomputers
M32C/83 group 
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER 
139
Timer Ai mode register 
(i = 0 to 4) (Event counter mode)
Symbol
TAiMR(i=0 to 4)
Address
When reset
00000X00
2
0356
16
, 0357
16
, 0358
16
, 0359
16
, 035A
16
Bit name
Function
Bit 
symbol
W
R
b7
b6
b5
b4
b3
b2
b1
b0
0 1 : Event counter mode
b1 b0 
TCK1
MR3
MR2
MR1
TMOD1
TMOD0 
TCK0
Operation mode 
select bit
This bit is invalid in M32C/80 series.
Port output control is set by the function select registers A, B and C.
Note 1: Count source is select by the event/trigger select bit (addresses 0342
16
, 0343
16
) in event counter mode. 
Note 2: This bit is valid when only counting an external signal.
Note 3: Set the corresponding function select register A to I/O port, and port direction register to 
“
0
”
. 
Signal of TAi
OUT
 pin counts down at the time of 
“
L
”
 and counts up at the time of 
“
H
”
.
Note 4: This bit is valid for timer A3 mode register. 
Timer A0 and A1 can be 
“
0
”
 or 
“
1
”
. 
Timer A2 is fixed to normal processing operation and timer A4 is fixed to multiply-by-4
             processing operation.
Note 5: When performing two-phase pulse signal processing, make sure the two-phase pulse 
signal processing operation select bit (address 0344
16
) is set to 
“
1
”
.  Also, always be
sure to set the event/trigger select bit (address 0343
16
) to 
“
00
”
.
0 (Set to 
“
0
”
 in Event counter mode)
(Note 1)
0 (Set to 
“
0
”
 when using 
two-phase pulse signal 
processing)
(When not using two-phase 
pulse signal processing)
(When using two-phase 
pulse signal processing)
Function
Count polarity 
select bit 
(Note 2)
0 : Counts external 
signal's falling edges
1 : Counts external 
signal's rising edges
Up/down 
switching cause 
select bit
0 : Up/down flag's content
1 : TAiOUT pin's input signal
                                (Note 3)
1 (Set to 
“
1
”
 when using 
two-phase pulse signal 
processing)
Count operation 
type select bit
0 : Reload type
1 : Free-run type
Two-phase pulse 
signal processing 
operation select 
bit  (Note 4,Note 5)
0 : Normal processing 
operation
1 : Multiply-by-4
processing operation
0 (Set to 
“
0
”
 when not 
using two-phase pulse 
signal processing)
MR0
Figure 1.14.8.  Timer Ai mode register in event counter mode