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117 lines
3.1 KiB
C
117 lines
3.1 KiB
C
/*
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* gpio.c
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*
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* Created on: Nov 14, 2020
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* Author: Doug
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*
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* Copyright (C) 2011-2020 Doug Brown
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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#include "../gpio.h"
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#include <avr/io.h>
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/// Struct representing the registers belonging to an AVR's GPIO port
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typedef struct AVRGPIORegs
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{
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/// Address of the PORT register for setting output value or enabling pullups
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volatile uint8_t *port;
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/// Address of the PIN register for reading input value or toggling outputs
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volatile uint8_t *pin;
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/// Address of the DDR register for setting whether pins are input or output
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volatile uint8_t *ddr;
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} AVRGPIORegs;
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/// The GPIO ports available on the AVR
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static AVRGPIORegs const gpioRegs[] = {
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{&PORTA, &PINA, &DDRA},
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{&PORTB, &PINB, &DDRB},
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{&PORTC, &PINC, &DDRC},
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{&PORTD, &PIND, &DDRD},
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{&PORTE, &PINE, &DDRE},
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{&PORTF, &PINF, &DDRF},
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};
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/** Sets the direction of a GPIO pin.
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*
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* @param pin The pin
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* @param output True if it should be an output, false if it should be an input
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*/
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void GPIO_SetDirection(GPIOPin pin, bool output)
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{
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if (output)
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{
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*(gpioRegs[pin.port].ddr) |= (1 << pin.pin);
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}
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else
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{
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*(gpioRegs[pin.port].ddr) &= ~(1 << pin.pin);
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}
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}
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/** Sets whether an input GPIO pin is pulled up
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*
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* @param pin The pin
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* @param pullup True if it should be pulled up, false if not
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*/
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void GPIO_SetPullup(GPIOPin pin, bool pullup)
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{
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// On the AVR, you set pullups using the PORT register that is ordinarily
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// used for setting the output value. You just have to make sure the pin
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// is configured as an input first. Otherwise you will modify the output.
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GPIO_Set(pin, pullup);
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}
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/** Turns a GPIO pin on (sets it high)
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*
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* @param pin The pin
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*/
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void GPIO_SetOn(GPIOPin pin)
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{
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*(gpioRegs[pin.port].port) |= (1 << pin.pin);
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}
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/** Turns a GPIO pin off (sets it low)
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*
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* @param pin The pin
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*/
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void GPIO_SetOff(GPIOPin pin)
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{
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*(gpioRegs[pin.port].port) &= ~(1 << pin.pin);
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}
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/** Toggles a GPIO pin
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*
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* @param pin The pin
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*/
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void GPIO_Toggle(GPIOPin pin)
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{
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// This is a tricky little hack the AVR provides that allows toggling
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// without a read/modify/write operation.
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*(gpioRegs[pin.port].pin) = (1 << pin.pin);
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}
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/** Reads the input status of a GPIO pin
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*
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* @param pin The pin
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* @return True if it's high, false if it's low
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*/
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bool GPIO_Read(GPIOPin pin)
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{
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return *(gpioRegs[pin.port].pin) & (1 << pin.pin);
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}
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