Atmel ATSAM3U-EK Data Sheet

6478E–ATARM–30-Mar-11

Figure 4-18.  User Buttons

The SAM3U-EK board is equipped with a three axis accelerometer MMA7341. Basically, it is an acceler-
ation to analog voltage converter. Converted data on corresponding directions are read by 3 SAM3U4E
12-bit ADC channels. 

PC13 controls the device sleep mode. A low level on PC13 will place the MMA7341 into sleep mode to 
reduce the current; conversely, a high PC13 level will wake it up from sleep mode. 

Jumper JP15 controls the device g-select function, which allows the selection between two sensitivity 
levels. Depending on the logic input placed on pin 10, the device internal gain will be changed, operating 
within a 3g or 11g range with different sensitivities.

Jumper JP16 provides control of the device self-test function. When the self-test function is initiated, an 
electrostatic force is applied to each axis to cause it to deflect. The x- and y-axis are deflected slightly 
while the z-axis is trimmed to deflect 1g. This procedure assures that both mechanical (g-cell) and elec-
tronic sections of the accelerometer are functioning.

Note that the 0-Ohm resistors R61/R62/R63 have been implemented to offer a disconnection possibility 
(freeing these dedicated PIO lines for other custom usage).

P A19

P A18

DG ND

BP_ RI GHT #

BP_ L E F T #

R 67
100R

R 67
100R

B P 4

B P 4

1

4

2

3

B P 5

B P 5

1

4

2

3

C 86

10nF

C 86

10nF

C 87

10nF

C 87

10nF

R 66
100R

R 66
100R

Table 4-2.  Direction

XOUT

PB3

AD2

YOUT

PC17

AD6

ZOUT

PC18

AD7

Table 4-3.  g-Select

0

3g

440mV/g

1

11g

117.5mV/g