Datasheet

12. Timer
page 97
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0020-2020B90JER
)T62/C61M,B62/C61M,A62/C61M(puorGA62/C61M
Item Specification
Count source f1, f2, f8, f32, fC32
Count operation • Down-count
• When the timer underflows, it reloads the reload register contents and continues counting
Divide ratio 1/(n+1) n: set value of TAi register (i= 0 to 4) 000016 to FFFF16
Count start condition Set TAiS bit in the TABSR register to “1” (= start counting)
Count stop condition Set TAiS bit to “0” (= stop counting)
Interrupt request generation timing Timer underflow
TAiIN pin function I/O port or gate input
TAiOUT pin function I/O port or pulse output
Read from timer Count value can be read by reading TAi register
Write to timer • When not counting and until the 1st count source is input after counting start
Value written to TAi register is written to both reload register and counter
• When counting (after 1st count source input)
Value written to TAi register is written to only reload register
(Transferred to counter when reloaded next)
Select function • Gate function
Counting can be started and stopped by an input signal to TAiIN pin
• Pulse output function
Whenever the timer underflows, the output polarity of TAiOUT pin is inverted.
When not counting, the pin outputs a low.
12.1.1. Timer Mode
In timer mode, the timer counts a count source generated internally (see Table 12.1.1.1). Figure 1.2.1.1.1
shows TAiMR register in timer mode.
Table 12.1.1.1. Specifications in Timer Mode
Timer Ai mode register (i=0 to 4)
Symbol Address After reset
TA0MR to TA4MR 0396
16 to 039A16 0016
Bit name FunctionBit symbol RW
b7 b6 b5 b4 b3 b2 b1 b0
Operation mode
select bit
0 0 : Timer mode
b1 b0
TMOD1
TMOD0
MR0
Pulse output function
select bit
0 : Pulse is not output
(TA
iOUT pin is a normal port pin)
1 : Pulse is output
(TA
iOUT pin is a pulse output pin)
Gate function select bit
0 0 :
Gate function not available
0 1 : (TAi
IN pin functions as I/O port)
1 0 : Counts while input on the TAi
IN pin
is low (1)
1 1 : Counts while input on the TAi
IN pin
is high (1)
b4 b3
MR2
MR1
MR3
Must be set to “0” in timer mode
0 0 : f
1 or f2
0 1 : f8
1 0 : f
32
1 1 : f
C32
b7 b6
TCK1
TCK0
Count source select bit
000
RW
RW
RW
RW
RW
RW
RW
RW
}
NOTE:
1.The port direction bit for the TAi
IN pin must be set to “0” (= input mode).
Figure 12.1.1.1. Timer Ai Mode Register in Timer Mode