
deveopmen
Timer B
Rev.B2 for proof reading
Mitsubishi Microcomputers
M32C/83 group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
150
(1) Timer mode
In this mode, the timer counts an internally generated count source. (See Table 1.15.1.) Figure 1.15.5
shows the timer Bi mode register in timer mode.
Table 1.15.1. Timer specifications in timer mode
Item
Specification
Count source
Count operation
f
1
, f
8
, f
2n
, f
C32
Counts down
When the timer underflows, it reloads the reload register contents before continuing
counting
1/(m+1)m : Set value
Count start flag is set (= 1)
Count start flag is reset (= 0)
Divide ratio
Count start condition
Count stop condition
Interrupt request generation timing
The timer underflows
TBiIN pin function
Read from timer
Write to timer
Programmable I/O port
Count value is read out by reading timer Bi register
When counting stopped
When a value is written to timer Bi register, it is written to both reload register and
counter
When counting in progress
When a value is written to timer Bi register, it is written to only reload register
(Transferred to counter at next reload time)
Figure 1.15.5. Timer Bi mode register in timer mode
Timer Bi mode register
(i = 0 to 5) (Timer mode)
Bit name
Function
Bit symbol
W
R
b7
b6
b5
b4
b3
b2
b1
b0
AA
Operation mode select bit
0 0 : Timer mode
TMOD1
MR0
TMOD0
Invalid in timer mode.
Can be
“
0
”
or
“
1
”
.
MR2
MR1
MR3
0 0 : f
1
0 1 : f
8
1 0 : f
2n
1 1 : f
C32
TCK1
TCK0
Count source select bit
Nothing is assigned. (i = 1, 2, 4, 5)
When write, set "0". When read, its content is indeterminate.
Invalid in timer mode. When write, set "0". When read in timer
mode, its content is indeterminate.
0 (Set to
“
0
”
in timer mode)
b7 b6
AA
AA
(Note 2)
A
A
AA
AA
Symbol
TBiMR(i=0 to 5)
Address
When reset
00XX0000
2
035B
16
, 035C
16
, 035D
16
, 031B
16
, 031C
16
, 031D
16
Note 1: R/W is valid only in timer B0 and timer B3.
Note 2: In timer B1, timer B2, timer B4 and timer B5, nothing is assigned by bit 4(There is not R/W).
When write, set
“
0
”
. When read, its content is indeterminate.
Note 3: n = 0 to 15. n is set by the count source prescaler register (address 035F
16
).
(Note 3)
(Note 1)