p2125vps20 Renesas Electronics Corporation., p2125vps20 Datasheet - Page 295

• Manufacturer Part Number: p2125vps20
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

If the MAXOVF flag is set to 1 while the CPSPE bit in TCMCR is set to 1, counting up by
TCMCNT stops and so does speed measurement. Subsequently clearing MAXOVF to 0
automatically clears TCMCNT to H'0000, and counting up for speed measurement is then
restarted.
Figure 12.8 shows an example of timing in speed measurement.
(3)
Either of two sets of conditions can be considered to represent fan-stopped states.
The fan can be considered to have stopped when a timer overflow is generated within the period
from the start of speed measurement mode to detection of the first edge (rising or falling as
selected with the IEDG bit in TCMCR).
Figure 12.9 shows an example of the timing of fan-stopped state (1).
TCMCYI
Input
capture signal
TCMCNT
TCMICR
φ
MAXOVF
TCMICRF
Determination of Fan Stoppage
Figure 12.8 Example of Timing in Speed Measurement
TCMCNT
cleared at
first rising edge
H'0000
Measurement cycle (TR)
A
Section 12 16-Bit Cycle Measurement Timer (TCM)
Rev. 1.00 Sep. 21, 2006 Page 257 of 658
D
Capture generated
TCMCNT
cleared at
third rising edge
REJ09B0310-0100
H'0000
D
When
TCMICR >
TCMMLCM
A