Update README.md

Author: alankrantas

README.md

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-# micropython-TTP229-BSF
+# MicroPython ESP8266/ESP32 Driver for TTP229-BSF 16-key Capacitive Keypad in Serial Interface Mode
+
+This MicroPython driver is for TTP229-BSF capacitive keypad on ESP8266/ESP3. Tested on both ESP8266 and ESP32 v1.11 firmware.
+
+The serial interface of TTP229-BSF <b>is not I2C</b> but it allows you to control this keypad via only 2 wires. Not to be confused with TTP229-LSF, which is a real I2C device.
+
+## Hardware Configuration
+
+TTP229-BSF's serial interface supports either 8 or 16 key mode, as well as single/multiple key mode. For some of the settings hardware configuration is required:
+
+![11-1035x1200](https://user-images.githubusercontent.com/44191076/69064016-6ec49c00-0a58-11ea-9b46-c10f4f1a9cdf.jpg)
+
+* TP2 not connected: 8 keys
+* TP2 connected (pulled low): 16 keys
+
+* TP3 and TP4 not connected: single key mode
+* TP3 and TP4 both connected (pulled low): multiple key mode
+
+Without any modification the TTP229-BSF is in 8-key/single mode. Connect the pins by wires or soldering to enable these options.
+
+## Wiring
+
+* VCC: 3.3V or 5V
+* GND: GND
+* SCL: scl pin (output)
+* SDO (not SDA): sdo pin (input)
+
+## Example
+
+```python
+from machine import Pin
+from TTP229_BSF import Keypad
+
+scl_pin = Pin(5, Pin.OUT)
+sdo_pin = Pin(4, Pin.IN)
+
+keypad = Keypad(scl=scl_pin, sdo=sdo_pin, inputs=16, multi=False)
+
+while True:
+    print(keypad.read())
+    # return a index number like 15 in single mode
+    # return a list like [0, 1, 14, 15] in multiple mode
+```
+
+<b>input</b> parameter:
+
+* input=8 (default): 8 key mode
+* input=16: 16 key mode
+
+<b>multi</b> parameter:
+
+* multi=False: single mode
+* multi=True: multiple mode
+
+In single mode keypad.read() will return the index of the pressed key (0~15). Return -1 when no key is pressed.
+
+In multiple mode keypad.read() will return a list containing all the indexes of pressed keys. Return an empty list when no key is pressed.
+
+If the TTP229-BSF is configured to multiple mode, read it in single mode will return the lowest index of all pressed keys. Read in multiple mode for a keypad configured in single mode, you'll get a list containing only one key index if any key is pressed.
+
+There's also a <b>raw</b> parameter. When set as True, keypad.read() will return the raw 8 or 16 key list indicating all keys' status (1=not pressed, 0=pressed).
+
+```python
+keypad = Keypad(scl=scl_pin, sdo=sdo_pin, inputs=16, multi=False, raw=True)
+# return a list like [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
+
+while True:
+    print(keypad.read())
+```
+
+If the keypad is configured to multiple mode and you read it in single/raw mode, you'll still get a list which shows multiple key pressing results.