Evaluation Kit Hardware
4-14
SAM3U-EK Development Board User Guide
6478B–ATARM–05-Oct-09
4.3.13
ADC Input
There are 8 multiplexed analog channel inputs on the 12-bit ADC, and 8 multiplexed analog channel
inputs on the 10-bit ADC. SAM3U-EK optionally connects the two ADC channels to BNC header (check
for your actual components implementation, schematics and BOM, on
http://www.atmel.com/products/
).
One is 12-bit ADC channel 3, shared with PIO pin PB4. The other one is 10-bit ADC channel 0, shared
with PIO PB5.
A potentiometer is also connected to these two channels to implement an easy access to ADC program-
ming and debugging (or implement an analog user control such as display brightness, volume, etc.).
Please note that SAM3U-EK default setting connects both AD12BAD3 and AD0 to the potentiometer so
that AD12BAD3 and AD0 are actually shorted. If these two ports need to work separately, R82 and/or
R84 should be removed.
There is another ADC application capability on SAM3U-EK (
See “G-Sensor” on page 4-15.
)
Figure 4-17.
ADC Input
4.3.14
User Buttons
2 user buttons on the SAM3U-EK are connected to PIO lines, and are defined as left and right buttons by
default.
ADC
P B 5
ADC
P B 4
DG ND
DG ND
DG ND
+3V 3
AD12BAD3
AD0
Pote nt i ome t e r
C N2
B NC
C N2
B NC
1
2
3
4
5
R 82
0R
R 82
0R
C N1
B NC
C N1
B NC
1
2
3
4
5
R 81
DNP
R 81
DNP
V R 1
10K
V R 1
10K
1
3
2
4
5
R 88
49.9R
R 88
49.9R
C 97
10nF
C 97
10nF
R 84
0R
R 84
0R
C 99
10nF
C 99
10nF
J P 18
J P
J P 18
J P
R 83
49.9R
R 83
49.9R
C 98
10nF
C 98
10nF
J P 19
J P
J P 19
J P
R 86
DNP
R 86
DNP
