Toshiba TLCS-900/H1 Series Data Book page 128

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Generating a 50% duty ratio square wave pulse
The state of the timer flip-flop (TA1FF1) is inverted at constant intervals and its
status output via the timer output pin (TA1OUT).
Example: To output a 2.4-µs square wave pulse from the TA1OUT pin at fsys = 20 MHz, use the
following procedure to make the appropriate register settings. This example uses timer 1;
however, either timer 0 or timer 1 may be used.
←
TA01RUN
←
TA01MOD
←
TA1REG
←
TA1FFCR
←
PCCR
←
PCFC
←
TA01RUN
Note: X = Don't care; "−" = No change
φ
T1
TA01RUN
<TA01RUN>
Bit7 ∼ 2
Up-
Bit 1
counter
0
Bit 0
Comparator
timing
Comparator output
(match detect)
INTTA1
UC1 Clear
TA1FF
TA1OUT
Figure 3.7.11 Square wave output timing chart (50% Duty)
7 6 5 4 3 2 1
– X X X – – 0
0 0 X X 0 1 –
0 0 0 0 0 0 1
X X X X 1 0 1
– – – – – – –
– – – – – – –
– X X X – 1 1
1 2 3
0
1.2 µ s at @fsys = 20 MHz
92CH21 - 124
0
– Stop TMRA1 and clear it to 0.
Select 8-Bit Timer Mode and select φ T1 (0.4 µs at fsys =
–
20 MHz) as the input clock.
Set the timer register to 2.4 µs ÷ φT1 ÷ 2 = 3
1
1 Clear TA1FF to 0 and set it to invert on the match detect
signal from timer 1.
1
Set PC0 to function as the TA1OUT pin.
1
– Start TMRA1 counting.
1 0
2 3
TMP92CH21
1 2 3 0