Rainbow Electronics ATAR862-3 - Manual (Page 61)

61
ATAR862-3
4556B–4BMCU–02/03
Timer 3 – Mode 12:
Timer/Counter with External
Capture Mode (T3I) The counter is driven by an internal clock source and an edge at the external input T3I
loads the counter value into the capture register. The edge can be selected with the pro-
grammable edge detector of the timer input stage. This mode can be used for signal and
pulse measurements.
Figure 62. External Capture Mode
Timer 3 Modulator for
Carrier Frequency Burst
Modulation If the output stage operates as pulse-width modulator for the shift register, the output
can be stopped with stage 1 of Timer 2. For this task, the timer mode 3 must be used
and the prescaler must be supplied by the internal shift clock of the shift register.
The modulator can be started with the start of the shift register (SIR = 0) and stopped
either by a shift register stop (SIR = 1) or compare match event of stage 1 of Timer 2.
For this task, the Timer 2 must be used in mode 3 and the prescaler stage must be sup-
plied by the internal shift clock of the shift register.
Figure 63. Modulator 3
Timer 3 Demodulator for
Biphase, Manchester and
Pulse-width-modulated
Signals The demodulator stage of Timer 3 can be used to decode Biphase, Manchester and
pulse-width-coded signals.
Figure 64. Timer 3 Demodulator 3
0 1 2 3 4 5 6 7 8 9 1011
Counter 3
T3CP-
Register
15
T3I
T3R
Capture value = X Capture value = 17
Capture
value = 35
0 121314 16 20 171819 22 21 23 27 242526 29 28 30 34 313233 36 35 37 41 383940
T3
Set Res
T3O
T3TOP
OMSK
TOG3
SO
SSI/
Control
M2
M3
MUX
T3M
0
1
2
3
Timer 3 Mode T3O
6 MUX 1
7 MUX 2
9 MUX 3
other MUX 0
Demodulator 3
T3EX Res
CM31 Counter 3
Reset
Counter 3
Control
SCI
SI
T3I
T3M