Class library for a 4x4 keypad connected to a MCP23008 I2C IO Expander.
MCP23008_Keypad.h
- Committer:
- grantphillips
- Date:
- 2016-04-04
- Revision:
- 2:e5ae44d8ac5b
- Parent:
- 1:470e527538a1
- Child:
- 3:7d6b9684595c
File content as of revision 2:e5ae44d8ac5b:
/* MCP23008_Keypad Library v1.0 * Copyright (c) 2016 Grant Phillips * grant.phillips@nmmu.ac.za * * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #ifndef MCP23008_Keypad_H #define MCP23008_Keypad_H #include "mbed.h" /** Class library for a 4x4 keypad connected to a MCP23008 I2C IO Expander. * The Keypad is assumed to be connected to the MCP23008 as follows: * * GP7 -> ROW4; GP6 -> ROW3; GP5 -> ROW2; GP4 -> ROW1; GP3 -> COL4; GP2 -> COL3; GP1 -> COL2; GP0 -> COL1 * * Example: * @code * #include "mbed.h" * #include "MCP23008_Keypad.h" * * MCP23008_Keypad keypad(PB_9, PB_6, 0x42); * * int main() { * char rcv; * int released = 1; * * while(1){ * rcv = keypad.ReadKey(); //read the current key pressed * * if(rcv == '\0') * released = 1; //set the flag when all keys are released * * if((rcv != '\0') && (released == 1)) { //if a key is pressed AND previous key was released * printf("%c\n", rcv); * released = 0; //clear the flag to indicate that key is still pressed * } * } * } * @endcode */ class MCP23008_Keypad { public: /** Create a MCP23008_Keypad object. * @param SDApin I2C compatible pin used for connecting to the MCP23008's SDA pin * @param SCLpin I2C compatible pin used for connecting to the MCP23008's SCL pin * @param MCP23008Address The I2C address of the MCP23008 to which the Keypad is connected. */ MCP23008_Keypad(PinName SDApin, PinName SCLpin, int MCP23008Address); /** Returns which key is currently is pressed. * @param * None * @return * The character representation of the key being pressed. Returns '\0' if no key is pressed. */ char ReadKey(); private: I2C i2c; int _addr; }; #endif