Atmel SAM4S-EK2 Atmel ATSAM4S-EK2 ATSAM4S-EK2 Data Sheet

11176A–ATARM–24-Sep-12

The BNC connector CN1 is connected to the ADC port PB1 as an external analog input. An on-board 50-
Ohm resistor termination can be applied by closing jumper JP16. A low pass filter can be implemented 
for the BNC connector CN1 by replacing R94 and C78 with custom resistor and capacitor values, 
depending on your application requirements.

A 10-KOhm potentiometer (VR1) is also connected to this channel to implement an easy access to ADC 
programming and debugging (or implement an analog user control like display brightness, volume, etc.). 

Either of these two functions can be selected by jumper JP18. 

Figure 4-16.  ADC Input

The BNC connector CN2 is connected to the DAC port PB13 and provides an external analog output. An 
on-board 50-Ohm resistor termination can be enabled by closing jumper JP21. A filter can be imple-
mented on this output channel by replacing R106 and C90 with appropriate resistor and capacitor 
values, depending on the application requirements.

Figure 4-17.  DAC Output

QTouch keys consist in a series of sensors formed by the association of a copper area and the capaci-
tive effect of human fingers approaching it.

The SAM4S-EK2 implements five individual capacitive touch keys (UP, DOWN, RIGHT, LEFT and 
VALID) using five pairs of PIO.

C7 8
10 nF

C8 9
10 nF

DG ND

JP 16
He ade r2

R9 6
49 .9R

VR1

10 K V R

1

3

2

DG ND

VCC3 3

JP 18

1

2

3

R9 4
0R

PB 1

CN1
BNC

R1 09
49 .9R

DG ND

JP 21
He ade r2

R1 06
0R

C9 0

2.2 uF

JP 30

1

2

3

AUDIO _O UTL

PB 13

CN2
BNC