Renesas M16C Series User Manual page 315

M30245 Group
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Figure 3.4.1. Set-up procedure of solution for a shortage of external interrupt pins
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
Initialization of timer A0
b7 b0
Timer A0 mode register
0 0 0 0 0 0 0 1
TA0MR [Address 0396
Selection of event counter mode
Pulse output function select bit
0 : Pulse is not output (TA0out pin is a normal port pin)
Count polarity select bit
0 : Counts external signal's falling edge
Up/down switching cause select bit
0 : Up/down flag's content
0 (Must always be "0" in event counter mode)
Count operation type select bit
0 : Reload type
When not using two-phase pulse signal processing, set this bit to "0"
b15 b8 b7
00 00
16 16
b7
b0
b7 b0
Up/down flag [Address 0384
0
UDF
Timer A0 up/down flag
0 : Down count
b7 b0
Count start flag [Address 0380
1
TABSR
b7 b0
One shot start flag [Address 0382
0 0 0
ONSF
Reserved bit (Must always be "0" )
Timer A0 event/trigger select flag
b7 b6
0 0 : Input on TA0
Note: Set the corresponding port direction register to "0".
Setting interrupt priority levels in timer A0
b7 b0
Timer A0 interrupt control register [Address 0054
TA0IC
Interrupt control level (set a value 1 to 7)
Initialization of port P7 direction register
b7 b0
Port P7 direction register [Address 03EF
0
PD7
Setting interrupt enable flag (I flag)
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]
16
b0
Timer A0 register
TA0 [Address 0387 , 0386
16
]
16
]
16
Timer A0 count start flag
1 : Starts counting
]
16
is selected (Note 1)
IN
Port P7 direction register
1
0 : Input mode
3. Timer A Applications
]
16
]
16
]
16