Fujitsu FR81S User Manual
CHAPTER 19: BASE TIMER
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER
: BASE TIMER
FUJITSU SEMICONDUCTOR CONFIDENTIAL
88
5.7.2. Operation during PWC Measurement
This section explains the operation during PWC measurement.
This section explains the operations during measurement. For explanation of "sensitive edges" (1) and (2)
described below, see "Figure 5-26 Measurement Modes and their Explanation 1" and "Figure 5-27
Measurement Modes and their Explanation 2".
Activation
Activate the 16/32-bit PWC timer with the following procedure:
Enable the 16/32-bit PWC timer operation by setting the CTEN bit of the timer control register (BTxTMCR)
to "1"(CTEN=1). The counter value is cleared to "0000
H
" and the 16/32-bit PWC timer waits for an input of
measurement start edge. (No counting occurs until an input of measurement start edge.)
Counting Operation
Operation in single measurement mode
If sensitive edge (1) is detected in the input signal (TIN) when a measurement start edge is waited, the up
counter starts counting up from "0001
H
" in synchronous with the count clock. If sensitive edge (2) is detected
in the input signal (TIN), the up counter stops from operating. During this time, the up counter value is stored
in the data buffer register (BTxDTBF). An interrupt request can be generated at the end of measurement or at
an occurrence of overflow.
Notes:
⋅
In the single measurement mode, the counting stops if an overflow occurs.
⋅
The input method of waveforms to be measured (TIN signal) varies depending on the I/O mode that has
been set by the I/O selection register (BTSEL01).
Operation in continuous measurement mode
If sensitive edge (1) is detected in the input signal (TIN) when a measurement start edge is waited, the up
counter starts counting up from "0001
H
" in synchronous with the count clock. If sensitive edge (2) is detected
in the input signal (TIN), the up counter stops from operating and waits for an input of measurement start
edge. During this time, the up counter value is stored in the data buffer register (BTxDTBF). If a rising edge
of the input signal (TIN) is detected when a measurement start edge is waited, the up counter starts counting
up from "0001
H
" again. An interrupt request can be generated at the end of measurement or at an occurrence
of overflow.
Note:
The input method of waveforms to be measured (TIN signal) varies depending on the I/O mode that has been
set by the I/O selection register (BTSEL01).
MB91520 Series
MN705-00010-1v0-E
721