(d) Count Mode and Count Operation
The count mode can be selected from five different modes. The mode determines which part of the
input pulse to measure. To accurately measure the width of high frequency pulses, a mode is available
to divide the input pulses by a specified ratio and to measure the resulting period. The following
describes each mode.
Count Mode
H pulse width
count
L pulse width
count
Rising edge to
rising edge
period count
Falling edge to
falling edge
period count
MB90580 Series
Table 18.4f Count Modes
MOD2 MOD1 MOD0
1
0
1
1
1
0
1
0
0
1
1
1
Count Operation
(w: Pulse width being measured)
W
⇑
⇓
Count start
Count stop
Measures the width of the "H" period.
• Count (meaOPsurement) start:
detected
• Count (measurement) end: Falling edge detected
W
⇓
⇑
Count start
Count stop
Measures the width of the "L" period.
• Count (measurement) start: Falling edge detected
• Count (measurement) end: Rising edge detected
W
W
⇑
⇑
Count start
Count stop
⇑
Start
Measures the time between rising edges.
• Count (measurement) start: Rising edge detected
• Count (measurement) end: Rising edge detected
W
W
⇓
⇓
Count start
Count stop
⇓
Start
Measures the time between falling edges
• Count (measurement) start: Falling edge detected
• Count (measurement) end: Falling edge detected
Chapter 18: Pulse Width Counter (PWC) Timer
18.4 Operations
W
⇑
⇓
Start
Stop
Rising edge
W
⇓
⇑
Start
Stop
W
⇑
Stop
⇑
⇑
Start
Stop
W
⇓
Stop
⇓
⇓
Start
Stop
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