CMT2157AW
Rev 0.8 | Page 21/31
www.hoperf.com
5.9 Button Modes
The button modes define the functions of the input pins K1 – K7. The CMT2157AW supports 4 different button modes: Normal,
Matrix, Toggle and PWM, which are configured on the RFPDK. The following sections give the abstract of each button mode.
All the details of the button modes are given in the document “AN142 CMT2157A Configuration Guideline”.
5.9.1 Normal
The Normal Button Mode is supported in 1920, 1527 and 2262 format. In this mode, the buttons are directly mapped to the
data field of the packet. Multiple buttons can be pressed at the same time. For 1920 and 1527, the largest number of buttons is
7 which are defined by the parameter “Number of Button(s)”. For 2262, the largest number of buttons is 6, which is determined
by the Sync ID Length. The figure below gives an example which 4 push button keys are selected.
LED
VDD
GND
RFO
K7
K6
K5
XTAL
CLK
K0
K1
K2
K3
K4
D0
D1
D2
D3
NC
NC
NC
NC
LED
VDD
GND
RFO
CLK
XTAL
7
6
5
1
2
3
4
8
9
10
14
13
12
11
√
√
√
√
×
×
×
√
√
√
√
√
√
×
Figure 23. Normal Button Mode
In normal button mode, the number of button(s) is used to determines the number of data bits in a packet. The table below
shows when 4 buttons are used and the pins K1 – K4 are mapped to the data D0 – D3, “1” in the Push Buttons section means
the corresponding button(s) is/are pressed, while the “1” in the Data Bits section means logic “1” to be transmitted.
Table 16. Mapping from K1-K4 to D0-D3 in Normal Button Mode
Push Buttons
The Data Bits
K1
K2
K3
K4
D0
D1
D2
D3
1
0
0
0
1
0
0
0
0
1
0
0
0
1
0
0
1
1
0
0
1
1
0
0
0
0
1
0
0
0
1
0
1
0
1
0
1
0
1
0
0
1
1
0
0
1
1
0
1
1
1
0
1
1
1
0
0
0
0
1
0
0
0
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
1
1
1
0
1
1
1
0
1
0
0
1
1
0
0
1
1
1
0
1
1
1
0
1
1
0
1
1
1
0
1
1
1
1
1
1
1
1
1
1
1
