Table 27-1. Majority Vote Filter
Samples [0, 1, 2]
Filter Output
[0,0,0]
0
[0,0,1]
0
[0,1,0]
0
[0,1,1]
1
[1,0,0]
0
[1,0,1]
1
[1,1,0]
1
[1,1,1]
1
When an external interrupt is configured for level detection and when filtering is disabled, detection is
done asynchronously. Asynchronuous detection does not require GCLK_EIC or CLK_ULP32K, but
interrupt and events can still be generated.
If filtering or edge detection is enabled, the EIC automatically requests GCLK_EIC or CLK_ULP32K to
operate. The selection between these two clocks is done by writing the Clock Selection bits in the Control
A register (
.CKSEL). GCLK_EIC must be enabled in the GCLK module.
Figure 27-2. Interrupt Detections
intreq_extint[x]
(edge detection / filter)
intreq_extint[x]
(edge detection / no filter)
intreq_extint[x]
(level detection / filter)
intreq_extint[x]
(level detection / no filter)
EXTINTx
CLK_EIC_APB
GCLK_EIC
clear INTFLAG.EXTINT[x]
No interrupt
No interrupt
The detection delay depends on the detection mode.
Table 27-2. Interrupt Latency
Detection mode
Latency (worst case)
Level without filter
Five CLK_EIC_APB periods
Level with filter
Four GCLK_EIC/CLK_ULP32K p five CLK_EIC_APB periods
Edge without filter
Four GCLK_EIC/CLK_ULP32K p five CLK_EIC_APB periods
Edge with filter
Six GCLK_EIC/CLK_ULP32K p five CLK_EIC_APB periods
Related Links
GCLK - Generic Clock Controller
on page 121
Atmel SAM L22G / L22J / L22N [DATASHEET]
Atmel-42402E-SAM L22G / L22J / L22N_Datasheet_Complete-07/2016
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