M30621ECGP MITSUBISHI [Mitsubishi Electric Semiconductor], M30621ECGP Datasheet - Page 83

• Manufacturer Part Number: M30621ECGP
• Description: SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

Timer B
Note: Timer B1 works exclusively as an internal timer since timer B1 does not have input port (TB1
Figure 1.13.18. Timer Bi mode register in event counter mode
Table 1.13.7. Timer specifications in event counter mode
Count source
Count operation
Divide ratio
Count start condition
Count stop condition
Interrupt request generation timing The timer underflows
TBi
Read from timer
Write to timer
(2) Event counter mode
In this mode, the timer counts an external signal or an internal timer's overflow. (See Table 1.13.7.)
Figure 1.13.18 shows the timer Bi mode register in event counter mode.
IN
pin function
Item
Timer Bi mode register
b7
b6
b5
b4
b3
b2
b1
0 1
• External signals input to TBi
• Effective edge of count source can be a rising edge, a falling edge, or falling
• Counts down
• When the timer underflows, it reloads the reload register contents before
1/(n+1)
Count start flag is set (= 1)
Count start flag is reset (= 0)
Count source input
Count value can be read out by reading timer Bi register
• When counting stopped
• When counting in progress
b0
and rising edges as selected by software
continuing counting
When a value is written to timer Bi register, it is written to both reload register and counter
When a value is written to timer Bi register, it is written to only reload register
(Transferred to counter at next reload time)
Note 1: Valid only when input from the TBi
Note 2: Timer B0, timer B3.
Note 3: Timer B1, timer B2, timer B4, timer B5.
Note 4: Set the corresponding port direction register to “0”. Since Timer B1 does not
Bit symbol
TMOD0
TMOD1
TCK0
TCK1
MR0
MR1
MR2
MR3
Symbol
TBiMR(i=0 to 5)
If timer's overflow is selected, this bit can be “0” or “1”. Since Timer B1 does
not have TB1
have TB1
Operation mode select bit
0 (Fixed to “0” in event counter mode; i = 0, 3)
Event clock select
Count polarity select
bit
Nothing is assigned (i = 1, 2, 4, 5).
In an attempt to write to this bit, write “0”. The value, if read, turns out
to be indeterminate.
Invalid in event counter mode.
In an attempt to write to this bit, write “0”. The value, if read in
event counter mode, turns out to be indeterminate.
Invalid in event counter mode. Can be “0” or “1”.
IN
(Note 1)
n : Set value
pin, do not use TB1
IN
Bit name
039B
035B
pin, the setting value of this bit is invaid.
Address
16
16
to 039D
to 035D
Specification
16
16
IN
IN
pin as event clock.
IN
pin
0 1 : Event counter mode
b3 b2
0 0 : Counts external signal's
0 1 : Counts external signal's
1 0 : Counts external signal's
1 1 : Inhibited
0 : Input from TBi
1 : TBj overflow
b1 b0
pin is selected as the event clock.
When reset
00XX0000
00XX0000
(j = i – 1; however, j = 2 when i = 0,
falling edges
rising edges
falling and rising edges
2
2
Function
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
IN
pin (Note 4)
j = 5 when i = 3)
M16C / 62 Group (80-pin)
(Note 2)
(Note 3)
R
Mitsubishi microcomputers
W
IN
).
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