TTP229-B

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Introduction

The TTP229-B is a chip used for touch pads. Typically the TTP229-B is used with 8 or 16 keys. Power requirements are 2.4V - 5.5V which makes them ideal to use with ESP Easy, the communication protocol is a proprietary serial variant but essentially only 4 cables (2 power, 2 communication) are needed for up to 16 keys. Please observe that the sibling module TTP229 is using I2C and thus not supported by ESP Easy!

TTP229 1.jpg

Hardware

    ESP            Keypad
    GPIO    <-->   SCL
    GPIO    <-->   SD0

    Power
    3.3V    <-->   VCC
    GND     <-->   GND

Please observe that you should NOT use default I2C pins since this will jam the I2C communication with the other I2C devices. This is because of the proprietary serial protocol, with clock (SCL) and bidirectional data (SDO), used by this module.


8 keys vs 16 keys

In order to get the 9-16 keys to work you need to bridge the P1.3 pair (see picture below). The setting will come active on boot of the module. Other settings is also possible but not covered in this guide.

TTP229 2.jpg

TTP229 3.jpg

ESP Easy

Use the device tab on the ESP Easy web interface and create a new task by editing one of the available tasks. Select "Keypad - ..." from the drop down box. TTP229 screendump.PNG

If you check "ScanCode" the key number will be reported and not the exponential numbering which is generally used when the module is set to allow multiple inputs simultaneously (if you use multi input the value will be the sum of all the pressed keys).

The values that this device reports will be as follows:

Key (ScanCode) Value (8 key) Value (16 key) Extra information
1 257 1
2 514 2
3 1028 4
4 2056 8
5 4112 16
6 8224 32
7 16448 64
8 32896 128
9 - 256
10 - 512
11 - 1024
12 - 2048
13 - 4096
14 - 8192
15 - 16384
16 - 32768