
R01UH0336EJ0102 Rev.1.02
Page 946 of 1538
Jul 17, 2014
V850E2/PG4-L
Section 17 OS Timer (OSTM)
17.3.5
Interval Timer Mode
Select the interval timer mode when an OS timer is to be used as a reference
timer for generating interrupt requests at a fixed interval.
(1)
Basic Operation in Interval Timer Mode
In interval timer mode, the timer counts down from the value specified in the
OSTMnCMP register. An OSTMnTINT interrupt request is generated when the
counter underflows (reaches 0000 0000
H
).
Select interval timer mode by setting OSTMnCTL.OSTMnMD1 = 0.
New values can be written to the OSTMnCMP register at any time. If it is
rewritten during count operation, the counter loads the new OSTMnCMP value
when the next 0000 0000
H
is reached. Then the counter continues with the
new value.
Periods of
OSTMnTINT and
OSTMnTTOUT
output
The periods of OSTMnTINT and OSTMnTTOUT output are as follows.
• OSTMnTINT generation period = counter-clock period
(OS 1)
• OSTMnTTOUT output period = OSTMnTINT generation period
2
The following figure shows the basic operation of the OS timer in interval timer
mode with counter-start interrupts enabled (OSTMnCTL.OSTMnMD0 = 1) and
OSTMnTTOUT output in timer-output toggling mode
(OSTMnTOE.OSTMnTOE = 1).
Figure 17-6
Timing Diagram of OS Timer in Interval Timer Mode
OSTMnTS
or OSTMnTSST
OSTMnTE
OSTMnCNT
OSTMnCMP
OSTMnTINT
OSTMnTTOUT
OSTMnTT
FFFF FFFF
0000 0000 H
H
A B
A A
B B
B B
B
A + 1
A + 1
B + 1
B + 1
B + 1
(1) (2) (2)
(2)
(2)
(4)
(2)
(3)
Содержание V850 Series
Страница 1556: ...V850E2 PG4 L R01UH0336EJ0102 Back Cover ...