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TMP92CZ26A
92CZ26A-286
b. Generating a 50% duty ratio square wave pulse
The state of the timer flip-flop (TA1FF) is inverted at constant intervals and its
status output via the timer output pin (TA1OUT).
Example: To output a 3.2μs square wave pulse from the TA1OUT pin at f
C
= 50 MHz,
use the following procedure to make the appropriate register settings. This
example uses TMRA1; however, either TMRA0 or TMRA1 may be used.
* Clock state Clcok gear : 1/1
Prescaler of clock gear : 1/2
7 6 5 4 3 2 1 0
TA01RUN
←
−
X X X
− −
0
−
Stop TMRA1 and clear it to “0”.
TA01MOD
←
0 0 X X 0 1 X X Select 8-bit timer mode and select φT1 (0.16 μs at f
C
= 50
MHz) as the input clock.
TA1REG
←
0 0 0 0 1 0 1 0 Set the timer register to 3.2 μs ÷ φT1 ÷ 2 = 0AH
TA1FFCR
←
X X X X 1 0 1 1 Clear TA1FF to “0” and set it to invert on the match detect
signal from TMRA1.
PM
←
−
X X X X
−
0X
PMFC
←
−
X X X X
−
1X
Set PM1 to function as the TA1OUT pin.
TA01RUN
←
−
X X X
−
11
−
Start TMRA1 counting.
X: Don’t care, −: No change
Figure 3.12.17 Square Wave Output Timing Chart (50% duty)
1.6
μ
s at f
C
=
50 MHz
0 1 2 3 0 1 2 3 0 1 2 3 0
φT1
TA01RUN
<TA01RUN>
Bit7 to Bit2
Bit1
Bit0
INTTA1
TA1FF
TA1OUT
Up
counter
Comparato
r
timing
Comparator output
(Match detect)
UC1 clea
r