mac-rom-simm-programmer/hal/at90usb646/gpio.c
Doug Brown 8b1cd63210 Change license to GPLv3
I can't use GPLv2 as soon as I need to start using the Nuvoton sample
code which is licensed with an Apache 2.0 license.
2023-09-10 05:02:44 -07:00

116 lines
2.9 KiB
C

/*
* gpio.c
*
* Created on: Nov 14, 2020
* Author: Doug
*
* Copyright (C) 2011-2023 Doug Brown
*
* 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 <https://www.gnu.org/licenses/>.
*
*/
#include "../gpio.h"
#include <avr/io.h>
/// Struct representing the registers belonging to an AVR's GPIO port
typedef struct AVRGPIORegs
{
/// Address of the PORT register for setting output value or enabling pullups
volatile uint8_t *port;
/// Address of the PIN register for reading input value or toggling outputs
volatile uint8_t *pin;
/// Address of the DDR register for setting whether pins are input or output
volatile uint8_t *ddr;
} AVRGPIORegs;
/// The GPIO ports available on the AVR
static AVRGPIORegs const gpioRegs[] = {
{&PORTA, &PINA, &DDRA},
{&PORTB, &PINB, &DDRB},
{&PORTC, &PINC, &DDRC},
{&PORTD, &PIND, &DDRD},
{&PORTE, &PINE, &DDRE},
{&PORTF, &PINF, &DDRF},
};
/** Sets the direction of a GPIO pin.
*
* @param pin The pin
* @param output True if it should be an output, false if it should be an input
*/
void GPIO_SetDirection(GPIOPin pin, bool output)
{
if (output)
{
*(gpioRegs[pin.port].ddr) |= (1 << pin.pin);
}
else
{
*(gpioRegs[pin.port].ddr) &= ~(1 << pin.pin);
}
}
/** Sets whether an input GPIO pin is pulled up
*
* @param pin The pin
* @param pullup True if it should be pulled up, false if not
*/
void GPIO_SetPullup(GPIOPin pin, bool pullup)
{
// On the AVR, you set pullups using the PORT register that is ordinarily
// used for setting the output value. You just have to make sure the pin
// is configured as an input first. Otherwise you will modify the output.
GPIO_Set(pin, pullup);
}
/** Turns a GPIO pin on (sets it high)
*
* @param pin The pin
*/
void GPIO_SetOn(GPIOPin pin)
{
*(gpioRegs[pin.port].port) |= (1 << pin.pin);
}
/** Turns a GPIO pin off (sets it low)
*
* @param pin The pin
*/
void GPIO_SetOff(GPIOPin pin)
{
*(gpioRegs[pin.port].port) &= ~(1 << pin.pin);
}
/** Toggles a GPIO pin
*
* @param pin The pin
*/
void GPIO_Toggle(GPIOPin pin)
{
// This is a tricky little hack the AVR provides that allows toggling
// without a read/modify/write operation.
*(gpioRegs[pin.port].pin) = (1 << pin.pin);
}
/** Reads the input status of a GPIO pin
*
* @param pin The pin
* @return True if it's high, false if it's low
*/
bool GPIO_Read(GPIOPin pin)
{
return *(gpioRegs[pin.port].pin) & (1 << pin.pin);
}