Fujitsu FR81S User Manual
CHAPTER 19: BASE TIMER
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER
: BASE TIMER
FUJITSU SEMICONDUCTOR CONFIDENTIAL
86
Note:
In the continuous measurement mode, if the next measurement is completed before the measurement result
has been read from the data buffer register (BTxDTBF), the value being held by the data buffer register
(BTxDTBF) is overwritten by the new value. The old value is discarded. If it has occurred, the ERR bit of the
status control register (BTxSTC) changes to "1". This ERR bit is cleared to "0" when a value is read from the
base timer x data buffer register (BTxDTBF).
Measurement Mode
Either of the following five modes can be selected using EGS2 to EGS0 bits of the timer control register
(BTxTMCR).
Figure 5-26 Measurement Modes and their Explanation 1
Measurement mode
(EGS2 to EGS0)
Measurement description
.
Count (measurement) start: at rising edge detection
Count (measurement) stop: at falling edge detection
Width
Width
Count start
Count stop
Start
Stop
Measurement of H pulse
width
(EGS2 to EGS0=000)
The width of the period which the "H" level signal is being input is measured.
The cycle from the falling edge detection to the next falling edge detection is measured.
Measurement of the cycle
between falling edges
(EGS2 to EGS0=010)
Count start
Period
Period
Period
Count stop
start
Count stop
start
Count (measurement) start: at falling edge detection
Count (measurement) stop: at falling edge detection
The cycle from the rising edge detection to the next rising edge detection is measured.
Count (measurement) start: at rising edge detection
Count (measurement) stop: at rising edge detection
Measurement of the cycle
between rising edges
(EGS2 to EGS0=001)
Period
Count start
Count stop
start
Period
Period
Count stop
start
MB91520 Series
MN705-00010-1v0-E
719