The Quadrature Decoder can be set in either X2 or X4 mode, which is configured in the QDM bit in TIMERn_CTRL. See
18.7 TIMER Quadrature Decoder Configuration on page 584
18.3.1.10 X2 Decoding Mode
In X2 Decoding mode, the counter increments or decrements on every edge of Channel A, see
Table 18.1 TIMER Counter Response in
Figure 18.8 TIMER X2 Decoding Mode on page 585
.
Table 18.1. TIMER Counter Response in X2 Decoding Mode
Channel B
Channel A
Rising
Falling
0
Increment
Decrement
1
Decrement
Increment
Channel A
Channel B
CNT
3
4
5
6
7
8
3
4
5
6
7
2
8
Figure 18.8. TIMER X2 Decoding Mode
18.3.1.11 X4 Decoding Mode
In X4 Decoding mode, the counter increments or decrements on every edge of Channel A and Channel B, see
Table 18.2 TIMER Counter Response in X4 Decoding Mode on page 585
.
Table 18.2. TIMER Counter Response in X4 Decoding Mode
Opposite Channel
Channel A
Channel B
Rising
Falling
Rising
Falling
Channel A = 0
Decrement
Increment
Channel A = 1
Increment
Decrement
Channel B = 0
Increment
Decrement
Channel B = 1
Decrement
Increment
Channel A
Channel B
3
4
5
6
7
8
9
10
11
3
4
5
6
7
8
9
10 11
2
2
CNT
Figure 18.9. TIMER X4 Decoding Mode
EFM32JG1 Reference Manual
TIMER - Timer/Counter
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