Basic library to interface to a Microchip MCP23016 I/O expander using I2C
Testing code to blink 2 lights
#include "mbed.h" #include "MCP23016.h" MCP23016 PortExpand(D4, D5, 0); DigitalOut myled(LED1); int main() { PortExpand.pinMode(0, DIR_OUTPUT); PortExpand.pinMode(8, DIR_OUTPUT); while(1) { PortExpand.digitalWrite(0, 1); PortExpand.digitalWrite(8, 0); myled = 1; // LED is ON wait(1); // 200 ms PortExpand.digitalWrite(0, 0); PortExpand.digitalWrite(8, 1); myled = 0; // LED is OFF wait(1); // 1 sec } }
Diff: MCP23016.h
- Revision:
- 0:133b7e09bbe7
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/MCP23016.h Tue Jan 19 23:50:23 2016 +0000 @@ -0,0 +1,136 @@ +/* MCP23016 library + Based on MCP23017 library for arduino by David Pye <davidmpye@gmail.com> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#ifndef MBED_MCP23016_H +#define MBED_MCP23016_H + +#include "mbed.h" + +#define GP0 0x00 // Access to GP0 +#define GP1 0x01 // Access to GP1 +#define OLAT0 0x02 // Access to OLAT0 +#define OLAT1 0x03 // Access to OLAT1 +#define IPOL0 0x04 // Access to IPOL0 +#define IPOL1 0x05 // Access to IPOL1 +#define IODIR0 0x06 // Access to IODIR0 +#define IODIR1 0x07 // Access to IODIR1 +#define INTCAP0 0x08 // Access to INTCAP0 (Read-Only) +#define INTCAP1 0x09 // Access to INTCAP1 (Read-Only) +#define IOCON0 0x0A // Access to IOCON0 +#define IOCON1 0x0B // Access to IOCON1 + +#define I2C_BASE_ADDRESS 0x40 + +#define DIR_OUTPUT 0 +#define DIR_INPUT 1 + +/** MCP23016 class + * + * Allow access to an I2C connected MCP23016 16-bit I/O extender chip + * Example: + * @code + * MCP23016 *par_port; + * @endcode + * + */ +class MCP23016 { +public: + /** Constructor for the MCP23016 connected to specified I2C pins at a specific address + * + * 16-bit I/O expander with I2C interface + * + * @param sda I2C data pin + * @param scl I2C clock pin + * @param i2cAddress I2C address + */ + MCP23016(PinName sda, PinName scl, int i2cAddress); + + /** Reset MCP23016 device to its power-on state + */ + void reset(void); + + /** Write a 0/1 value to an output bit + * + * @param value 0 or 1 + * @param bit_number bit number range 0 --> 15 + */ + void write_bit(int value, int bit_number); + + /** Write a masked 16-bit value to the device + * + * @param data 16-bit data value + * @param mask 16-bit mask value + */ + void write_mask(unsigned short data, unsigned short mask); + + /** Read a 0/1 value from an input bit + * + * @param bit_number bit number range 0 --> 15 + * @return 0/1 value read + */ + int read_bit(int bit_number); + + /** Read a 16-bit value from the device and apply mask + * + * @param mask 16-bit mask value + * @return 16-bit data with mask applied + */ + int read_mask(unsigned short mask); + + /** Configure an MCP23016 device + * + * @param dir_config data direction value (1 = input, 0 = output) + * @param polarity_config polarity value (1 = flip, 0 = normal) + */ + void config(unsigned short dir_config, unsigned short polarity_config); + + void writeRegister(int regAddress, unsigned char val); + void writeRegister(int regAddress, unsigned short val); + int readRegister(int regAddress); + +/*----------------------------------------------------------------------------- + * pinmode + * Set units to sequential, bank0 mode + */ + void pinMode(int pin, int mode); + void digitalWrite(int pin, int val); + int digitalRead(int pin); + +// These provide a more advanced mapping of the chip functionality +// See the data sheet for more information on what they do + +//Returns a word with the current pin states (ie contents of the GPIO register) + unsigned short digitalWordRead(); +// Allows you to write a word to the GPIO register + void digitalWordWrite(unsigned short w); +// Sets up the polarity mask that the MCP23016 supports +// if set to 1, it will flip the actual pin value. + void inputPolarityMask(unsigned short mask); +//Sets which pins are inputs or outputs (1 = input, 0 = output) NB Opposite to arduino's +//definition for these + void inputOutputMask(unsigned short mask); + int read(void); + void write(int data); + +protected: + I2C _i2c; + int MCP23016_i2cAddress; // physical I2C address + unsigned short shadow_GPIO, shadow_IODIR, shadow_IPOL; // Cached copies of the register values + +}; + +#endif \ No newline at end of file