p2125vps20 Renesas Electronics Corporation., p2125vps20 Datasheet - Page 296

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

Section 12 16-Bit Cycle Measurement Timer (TCM)
Speed measurement stops if MAXOVF is set to 1 while the CPSPE bit in TCMCR is set to 1.
Subsequently clearing MAXOVF to 0 restarts speed measurement. In this case, the fan can be
considered to have stopped if a timer overflow is generated before detection of the first edge.
Figure 12.10 shows an example of the timing of the fan-stopped state (2).
Rev. 1.00 Sep. 21, 2006 Page 258 of 658
REJ09B0310-0100
φ
TCMCYI
CPSPE
TCMCNT
OVF
MAXOVF
TCMCYI
φ
TCMMDS
TCMCNT
OVF
MAXOVF
Figure 12.10 Example of Timing in Fan-Stopped State (2)
Figure 12.9 Example of Timing in Fan-Stopped State (1)
H'5555
H'0000
Restart of measurement
H'0000
H'FFFF
H'FFFF
H'0000
MAXOVF flag is not set
because the first cycle measurement is not started
Determined as fan-stopped state
H'0000
MAXOVF flag is not set
because the first cycle measurement is not started
Determined as fan-stopped state
H'0001
H'0001
Start of first measurement
H'0000
Start of first measurement
H'0000