Rainbow Electronics ATAR862-3 - Manual (Page 85)

85
ATAR862-3
4556B–4BMCU–02/03
Figure 87. Frequency Measurement
Figure 88. Event Counter with Time Gate
Combination Mode 11:
Burst Modulation 1 Timer 2 mode 1/2: 12-bit compare counter/8-bit compare counter and
4-bit prescaler
Timer 2 output mode 1/6: Timer 2 compare match toggles the output flip-flop (M2)
to the Timer 3
Timer 3 mode 6: Carrier frequency burst modulation controlled by Timer 2
output (M2)
The Timer 3 counter is driven by an internal or external clock source. Its compare and
compare mode registers must be programmed to generate the carrier frequency with
the output toggle flip-flop. The output toggle flip-flop (M2) of Timer 2 is used to enable
and disable the Timer 3 output. The Timer 2 can be driven by the toggle output signal of
Timer 3 (TOG3) or any other clock source.
Figure 89. Burst Modulation 1
0 0 1 2 3 4 5 6 7 8 9 10
Counter 3
TOG2
T3CP-
Register
T3I
T3R
Capture value = 0 Capture value = 17 Capt. value = 18
11121314151617 1 2 3 4 5 6 7 8 9 101112131415161718 0 0 1 2 3 4 5
0 0 1 2 3 4 5 6 7 8 9 10
Counter 3
TOG2
T3CP-
Register
11 0 1 2 4 0 1
T3I
2 3
T3R
Capture value = 0 Capture value = 11 Cap. val. = 4
0 1 0 1 2 3 4 5 0 1 0 1 2 3 4 5 0 1 0 1 2 3 4 5 0 1 0 1 5 0 1 0 1 5 0 1 0 1 5 0 1 0 1 5 0 1 0 1 5 0 1 0 1 5 0 1 0 1 5 0 1 0 1 5 0 1 0 1 5 0 1 0 1
3 0 1 2 3 3 0 1 3 2
CL3
Counter 3
CM1
CM2
TOG3
M3
Counter 2/2
TOG2
M2
T3O