159
CHAPTER 8 PULSE WIDTH COUNT TIMER (PWC)
8.6
Operation of Pulse Width Measurement Function
This section describes the operations of the pulse width measurement function of the
pulse width count timer.
■
Operation of pulse width measurement function
Figure 8.6-1 "Pulse width measurement function settings" shows the settings required to operate as the
pulse width measurement function.
Figure 8.6-1 Pulse width measurement function settings
When counter operation is enabled, the counter starts to count down from "FF
H
" when a measurement start
edge is detected on the pulse input to the PWC pin. (For "H" level measurement, the counter starts
measurement from the next rising edge if the input is already "H".)
On detection of the measurement completion edge, the current down counter value is transferred to the
PWC reload buffer register (RLBR), the measurement completion interrupt request flag bit (PCR1: IR) and
buffer full flag bit (PCR1: BF) are both set to "1", and counter operation is re-enabled. (The function
supports continuous pulse width measurement and so can be used like an input capture.)
Figure 8.6-2 "Example of "H" width measurement using pulse width measurement function" shows the
operation when the measured pulse selection bits (PCR2: W1, W0) are set to "00
B
" ("H" width
measurement).
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
DDR4
0
PCR1
EN
IE
UF
IR
BF
1
PCR2
FC
RM
TO
C1
C0
W1
W0
1
RLBR
Holds the pulse width measurement value.
: Used bit
: Used to
measure long
pulse widths
: Unused bit
1 : Set "1".
0 : Set "0".
X
X
X
X
X
X
X
X
X
X
Summary of Contents for MB89950 Series
Page 2: ......
Page 3: ...FUJITSU LIMITED F2MC 8L 8 BIT MICROCONTROLLER MB89950 950A Series HARDWARE MANUAL ...
Page 4: ......
Page 10: ...vi ...
Page 34: ...20 CHAPTER 2 HANDLING DEVICES ...
Page 134: ...120 CHAPTER 6 WATCHDOG TIMER ...
Page 236: ...222 CHAPTER 10 UART ...
Page 276: ...262 CHAPTER 12 LCD CONTROLLER DRIVER ...
Page 310: ...296 APPENDIX ...
Page 311: ...297 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Page 316: ...302 INDEX ...
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