CHAPTER 7 TIMER/COUNTER FUNCTION
User’s Manual U13850EJ6V0UD
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(7) Operation of OVFn bit
(a) OVFn bit set
The OVFn bit is set to 1 in the following case in addition to when the TMn register overflows:
Select the mode in which the timer is cleared and started on a match between TMn and CRn0 or the mode in
which it is cleared and started by the valid edge of TIn0.
↓
Set CRn0 to FFFFH.
↓
When TMn is cleared from FFFFH to 0000H on a match with the CRn0 register
Figure 7-30. Operation Timing of OVFn Bit
Remark
n = 0, 1
(b) Clear OVFn bit
Even if the OVFn bit is cleared before the next count clock is counted (before TMn become 0001H) after
TMn has overflowed, the OVFn flag is set again and the clear becomes invalid.
(8) Conflict operation
(a) If the read period and capture trigger input conflict
When 16-bit capture/compare registers n0 and n1 (CRn0, CRn1) are used as capture registers, if the read
period and capture trigger input conflict, the capture trigger has priority. The read data of CRn0 and CRn1 is
undefined.
(b) If the match timings of the write period and TMn conflict
When 16-bit capture/compare registers n0 and n1 (CRn0, CRn1) are used as capture registers, because
match detection cannot be performed correctly if the match timings of the write period and 16-bit timer
register n (TMn) conflict, do not write to CRn0 and CRn1 close to the match timing.
(9) Timer operation
(a) CRn1 capture
Even if 16-bit timer register n (TMn) is read, a capture to 16-bit capture/compare register n1 (CRn1) is not
performed.
(b) Acknowledgment of TIn0 and TIn1 pins
When the timer is stopped, input signals to the TIn0 and TIn1 pins are not acknowledged, regardless of the
CPU operation.
Count pulse
CRn0
0001H
0000H
FFFFH
FFFEH
FFFFH
TMn
OVFn
INTTMn0
Содержание V850/SB1
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