
Timer B
Unde
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Preliminary Specifications REV.E
Specifications in this manual are tentative and subject to change.
Mitsubishi microcomputers
M30220 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
81
Item
Specification
Count source
Count operation
f
1
, f
8
, f
32
, f
C132
Counts down
When the timer underflows, it reloads the reload register contents before
continuing counting
1/(n+1)
n : Set value
Count start flag is set (= 1)
Count start flag is reset (= 0)
The timer underflows
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)
Divide ratio
Count start condition
Count stop condition
Interrupt request generation timing
TBi
IN
pin function
Read from timer
Write to timer
(1) Timer mode
In this mode, the timer counts an internally generated count source. (See Table 1.13.6.) Figure 1.13.19
shows the timer Bi mode register in timer mode.
Table 1.13.6. Timer specifications in timer mode
Note 1: Timer B0, timer B3.
Note 2: Timer B1, timer B2, timer B4, timer B5.
Timer Bi mode register
AA
Symbol
TBiMR(i=0 to 2)
TBiMR(i=3 to 5)
Address
When reset
00XX0000
2
00XX0000
2
039B
16
to 039D
16
035B
16
to 035D
16
Bit name
Function
Bit symbol
b7
b6
b5
b4
b3
b2
b1
0
b0
0
AA
Operation mode select bit
0 0 : Timer mode
TMOD1
TMOD0
MR0
MR1
Invalid in timer mode
Can be “0” or “1”
MR2
MR3
0 0 : f
1
0 1 : f
8
1 0 : f
32
1 1 : f
C132
TCK1
TCK0
Count source select bit
Invalid in timer mode.
In an attempt to write to this bit, write “0”. The value, if read in
timer mode, turns out to be indeterminate.
0 (Fixed to “0” in timer mode ; i = 0, 3)
Nothing is assiigned (i = 1, 2, 4, 5).
In an attempt to write to this bit, write “0”. The value, if read, turns out
to be indeterminate.
(Note 1)
AAA
(Note 2)
A
b7 b6
AAA
AAA
AAA
AAA
AAA
A
Figure 1.13.19. Timer Bi mode register in timer mode