Atmel ATSAM3U-EK Data Sheet

6478E–ATARM–30-Mar-11

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 (

)

Figure 4-17.  ADC Input

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