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R01UH0336EJ0102 Rev.1.02
Page 952 of 1538
Jul 17, 2014
V850E2/PG4-L
Section 17 OS Timer (OSTM)
(2)
Operation when OSTMnCMP = 0000 0000
H
The following figure shows the operation of the OS timer when OSTMnCMP =
0000 0000
H
, counter-start interrupts are enabled (OSTMnCTL.OSTMnMD0 =
1), and OSTMnTTOUT is in timer-output toggling mode
(OSTMnTOE.OSTMnTOE = 1).
Figure 17-10
Timing Diagram when OSTMnCMP = 0000 0000
H
in Free-Running
Comparison Mode with PCLK Selected as the Counter Clock
(OSTMnTCKE Is High)
The above timing diagram shows the following operations.
1. Once the counter starts, it counts up from 0000 0000
H
to FFFF FFFF
H
.
2. An OSTMnTINT interrupt request is generated when counting starts (and
the OSTMnTTOUT output is toggled).
3. The OSTMnTTOUT output is toggled. A comparison interrupt is only
generated if the current value of the counter matches that in the
OSTMnCMP register.
Note
When PCLK is selected as the counter clock (OSTMnTCKE is high) and the
value for comparison is 0 (OSTMnCMP = 0000 0000
H
), OSTMnTINT initially
stays at the high level over two cycles of PCLK, and one interrupt request is
generated for every rising edge of OSTMnTINT.
PCLK
OSTMnTCKE
OSTMnTS
or OSTMnTSST
OSTMnTE
OSTMnCMP
OSTMnCNT
OSTMnTINT
OSTMnTTOUT
FFFF FFFF
0000 0000 H
H
0000 0000 H
Fixed to 1
(1) (2) (3)
(3)
(3)
(3)
Counting operation