Nordic 3 - Page 32

5 Hardware description: Smart Remote 3 DK add-on
Doc. ID 4374_139 v1.1
Page 32
K
E
Y
O
U
T_
0
KEYIN_1
KEYIN_2
KEYIN_3
KEYIN_4
KEYIN_0
K1
*
K9
6
K21
TBD
K32
Menu
K40
UP
K17
K2
0
K10
1
K22
TBD
K33
Down
K41
TBD
K18
K3
#
K11
2
K23
V_Down
K34
Exit
K42
TV
K4
7
K12
3
K24
Mute
K35
Left
K43
SAT
K5
8
K13
Red
K25
C_Down
K36
OK
K44
DVD
K6
9
K14
Green
K26
V_Up
K37
Right
K45
AUX
K7
4
K15
Yellow
K27
Back
K38
TBD
K46
Power
K8
5
K16
Blue
K28
C_Up
K47
TBD
K
E
Y
O
U
T
_
1
K
E
Y
O
U
T
_
2
K
E
Y
O
U
T
_
3
K
E
Y
O
U
T_
4
K
E
Y
O
U
T
_
5
K
E
Y
O
U
T
_
6
K
E
Y
O
U
T
_
7
K19
K20
K29
K30
K31
K39
KEYIN_5
SW1
MB Left
SW2
MB Right
Figure 18: Keypad matrix
The matrix is connected to an I/O expander that is controlled by the nRF device using I
2
C. See Figure 19:
Keypad matrix I/O expander on page 33.
The I/O expander circuit is added on the DK add-on so that it strictly uses the I/O set available in the Arduino
interface system. On the Product example - where no Arduino interface is used - the I/O expander circuit is not
needed.