This library provides simplified I2C access to a Microchip MCP23x17 GPIO expender device, including a general interface for any GPIO expender
Diff: AbstractGpioExpender.h
- Revision:
- 2:3bea48e1505c
- Parent:
- 1:ec9e770173d5
--- a/AbstractGpioExpender.h Fri Jan 09 15:35:40 2015 +0000 +++ b/AbstractGpioExpender.h Tue Jan 13 10:09:01 2015 +0000 @@ -1,3 +1,21 @@ +/* mbed simplified interface for GPIO expender (e.g. Microchip MCP23x17) + * Copyright (c) 2014-2015 ygarcia, MIT License + * + * 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. + */ #pragma once #include <list> @@ -24,6 +42,8 @@ #define GPIO_MED GPB0 #define GPIO_SIZE 8 +/** This class describes a simplified interface for GPIO expender (e.g. Microchip MCP23x17) + */ class AbstractGpioExpender { public: /** Interrupt modes @@ -34,40 +54,68 @@ OnFalling = 0x03 }; + /** Pull modes + */ + enum PullModes { + PullOff = 0x00, + PullUp = 0x01, + PullDown = 0x03 + }; + /** Reset the device */ virtual void reset() = 0; - /** Setup interrupt mechanism for all GPIO ports + /** Setup device interrupt mechanism * @param p_mirroring Set to 0x00 to disable INTA/B mirroring, 0x01 otherwise. Default: 0x00 * @param p_openDrain Set to 0x00 for active driver output, 0x01 for opn drain output. Default: 0x00 * @param p_polarity Set to 0x00 for interrupt active low, 0x01 otherwise. Default: 0x00 */ virtual void setupInterrupts(const unsigned char p_mirroring = 0x00, const unsigned char p_openDrain = 0x00, const unsigned char p_polarity = 0x00) = 0; - /** Setup interrupt for a specific IO port + /** Setup interrupt mode for a specific IO port * @param p_gpioId The IO port identifier * @param p_mode The interrupt mode - * @return 0 on success, negative value otherwise + * @return 0 on success, -1 on wrong parameters and -2 otherwise */ virtual int setupInterruptPin(const unsigned char p_gpioId, const InterruptModes p_mode = OnRising) = 0; + /** Setup pull mode for a specific IO port + * @param p_gpioId The IO port identifier + * @param p_mode The interrupt mode + * @return 0 on success, -1 on wrong parameters and -2 otherwise + */ + virtual int setupPullPin(const unsigned char p_gpioId, const PullModes p_mode = PullOff) = 0; + /** Get interrupt information and clear it * @param p_gpioId The IO port identifier where the interrupt occured * @param p_value The logic value on the pin port where the interrupt occured - * @return 0 on success, negative value otherwise + * @return 0 on success, -1 on wrong parameters and -2 otherwise */ - virtual int getLastInterruptPin(unsigned char * p_gpioId, unsigned char * p_value) = 0; + virtual int getLastInterruptPinAndValue(unsigned char * p_gpioId, unsigned char * p_value) = 0; /** Attach a function to call when a interrupt occurs on the GPIOA input ports + * @param p_fptr The pointer to the "C" callback function */ virtual void setIntrACallback(void (* p_fptr)(void)) = 0; - /** Attach a function to call when a rising edge occurs on the input + /** Attach a function to call when a interrupt occurs on the GPIOB input ports + * @param p_fptr The pointer to the "C" callback function */ virtual void setIntrBCallback(void (* p_fptr)(void)) = 0; + /** Read the specific GPIO port pin + * @param p_gpioId The GPIO port pin to be read + * @param p_value The GPIO port pin value + * @return 0 on success, -1 on wrong parameters and -2 otherwise + */ virtual int read(const unsigned char p_gpioId, unsigned char * p_value) = 0; + + /** Write value to the specific GPIO port pin + * @param p_gpioId The GPIO port pin to be written + * @param p_value The GPIO port pin value + * @return 0 on success, -1 on wrong parameters and -2 otherwise + */ virtual int write(const unsigned char p_gpioId, const unsigned char p_value) = 0; virtual unsigned char createBus(const std::list<unsigned char> p_lines, const PinMode p_mode = PullNone) = 0;