TWR-K20D72M User’s Manual
Page 11 of 17
are connected to a Touch Tower Plug-in (TWRPI) socket that can accept Touch TWRPI daughter cards
that may feature keypads, rotary dials, sliders, etc.
The pinout for the Touch TWRPI socket is defined in Table 3. Refer to Table 5 “I/O Connectors and Pin
Usage Table” for the specific K20 pin connections to the Touch TWRPI socket.
Table 3.
Touch TWRPI Pin Description
Pin Description
1
5V VCC
2
3.3 V VCC
3
Electrode 0
4
3.3V VDDA
5
Electrode 1
6
VSS (Analog GND)
7
Electrode 2
8
Electrode 3
9
Electrode 4
10 Electrode 5
11 Electrode 6
12 Electrode 7
13 Electrode 8
14 Electrode 9
15 Electrode 10
16 Electrode 11
17 ADC: TWRPI ID 0
18 ADC: TWRPI ID 1
19 GND
20 Reset
2.12
Microphone and buzzer
TWR-K20D72M board includes a microphone U16 which connects with one ADC channel to allow audio
recording, there is a low-pass filter implemented before microphone input goes to ADC channel.
Jumper J4 can be used for connection with the ADC channel. There is also a buzzer connected with one
PWM output channel on FTM module, jumper J21 is used for this connection.
