ATAM894 Datasheet, PDF (54/97 Pages) ATMEL Corporation – 8k-flash Microcontroller

6.3.3.4
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 programmable edge
detector of the timer input stage. This mode can be used for signal and pulse measurements.
Figure 6-35. External Capture Mode
T3R
T3I
Counter 3
T3CP-
Register
0 0 1 2 3 4 5 6 7 8 9 1011 12 13 14 15 16 1718 19 20 21 22 23 24 2526 2728 29 30 3132 33 34 35 3637 3839 40 41
Capture value = X
Capture value = 17
Capture value = 35
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 supplied by the internal shift
clock of the shift register.
Figure 6-36. Modulator 3
TOG3
SO
M2
SSI/
Control
T3
M3
Set Res
T3TOP
0
1
2 _MUX
T3O
OMSK
3
T3M
Timer 3 Mode T3O
6 MUX 1
7 MUX 2
9 MUX 3
other MUX 0
54 ATAM894
4679D–4BMCU–05/05