207 lines
6.5 KiB
C
207 lines
6.5 KiB
C
/** @addtogroup gpio_file
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@author @htmlonly © @endhtmlonly 2009
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Uwe Hermann <uwe@hermann-uwe.de>
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@author @htmlonly © @endhtmlonly 2012
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Ken Sarkies <ksarkies@internode.on.net>
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Each I/O port has 16 individually configurable bits. Many I/O pins share GPIO
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functionality with a number of alternate functions and must be configured to
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the alternate function mode if these are to be accessed. A feature is available
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to remap alternative functions to a limited set of alternative pins in the
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event of a clash of requirements.
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The data registers associated with each port for input and output are 32 bit
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with the upper 16 bits unused. The output buffer must be written as a 32 bit
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word, but individual bits may be set or reset separately in atomic operations
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to avoid race conditions during interrupts. Bits may also be individually
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locked to prevent accidental configuration changes. Once locked the
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configuration cannot be changed until after the next reset.
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Each port bit can be configured as analog or digital input, the latter can be
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floating or pulled up or down. As outputs they can be configured as either
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push-pull or open drain, digital I/O or alternate function, and with maximum
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output speeds of 2MHz, 10MHz, or 50MHz.
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On reset all ports are configured as digital floating input.
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@section gpio_api_ex Basic GPIO Handling API.
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Example 1: Push-pull digital output actions with pullup on ports C2 and C9
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@code
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gpio_mode_setup(GPIOC, GPIO_MODE_OUTPUT,
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GPIO_PUPD_PULLUP, GPIO2 | GPIO9);
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gpio_set_output_options(GPIOC, GPIO_OTYPE_PP,
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GPIO_OSPEED_25MHZ, GPIO2 | GPIO9);
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gpio_set(GPIOC, GPIO2 | GPIO9);
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gpio_clear(GPIOC, GPIO2);
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gpio_toggle(GPIOC, GPIO2 | GPIO9);
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gpio_port_write(GPIOC, 0x204);
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@endcode
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Example 2: Digital input on port C12 with pullup
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@code
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gpio_mode_setup(GPIOC, GPIO_MODE_INPUT,
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GPIO_PUPD_PULLUP, GPIO12);
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reg16 = gpio_port_read(GPIOC);
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@endcode
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*/
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/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2011 Fergus Noble <fergusnoble@gmail.com>
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*
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* This library is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This library 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 Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**@{*/
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#include <libopencm3/stm32/gpio.h>
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/*---------------------------------------------------------------------------*/
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/** @brief Set GPIO Pin Mode
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Sets the Pin Direction and Analog/Digital Mode, and Output Pin Pullup,
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for a set of GPIO pins on a given GPIO port.
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@param[in] gpioport Unsigned int32. Port identifier @ref gpio_port_id
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@param[in] mode Unsigned int8. Pin mode @ref gpio_mode
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@param[in] pull_up_down Unsigned int8. Pin pullup/pulldown configuration @ref
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gpio_pup
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@param[in] gpios Unsigned int16. Pin identifiers @ref gpio_pin_id
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If multiple pins are to be set, use bitwise OR '|' to separate
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them.
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*/
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void gpio_mode_setup(uint32_t gpioport, uint8_t mode, uint8_t pull_up_down,
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uint16_t gpios)
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{
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uint16_t i;
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uint32_t moder, pupd;
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/*
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* We want to set the config only for the pins mentioned in gpios,
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* but keeping the others, so read out the actual config first.
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*/
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moder = GPIO_MODER(gpioport);
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pupd = GPIO_PUPDR(gpioport);
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for (i = 0; i < 16; i++) {
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if (!((1 << i) & gpios)) {
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continue;
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}
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moder &= ~GPIO_MODE_MASK(i);
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moder |= GPIO_MODE(i, mode);
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pupd &= ~GPIO_PUPD_MASK(i);
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pupd |= GPIO_PUPD(i, pull_up_down);
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}
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/* Set mode and pull up/down control registers. */
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GPIO_MODER(gpioport) = moder;
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GPIO_PUPDR(gpioport) = pupd;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief Set GPIO Output Options
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When the pin is set to output mode, this sets the configuration (analog/digital
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and open drain/push pull) and speed, for a set of GPIO pins on a given GPIO
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port.
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@param[in] gpioport Unsigned int32. Port identifier @ref gpio_port_id
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@param[in] otype Unsigned int8. Pin output type @ref gpio_output_type
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@param[in] speed Unsigned int8. Pin speed @ref gpio_speed
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@param[in] gpios Unsigned int16. Pin identifiers @ref gpio_pin_id
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If multiple pins are to be set, use bitwise OR '|' to separate
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them.
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*/
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void gpio_set_output_options(uint32_t gpioport, uint8_t otype, uint8_t speed,
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uint16_t gpios)
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{
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uint16_t i;
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uint32_t ospeedr;
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if (otype == 0x1) {
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GPIO_OTYPER(gpioport) |= gpios;
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} else {
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GPIO_OTYPER(gpioport) &= ~gpios;
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}
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ospeedr = GPIO_OSPEEDR(gpioport);
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for (i = 0; i < 16; i++) {
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if (!((1 << i) & gpios)) {
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continue;
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}
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ospeedr &= ~GPIO_OSPEED_MASK(i);
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ospeedr |= GPIO_OSPEED(i, speed);
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}
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GPIO_OSPEEDR(gpioport) = ospeedr;
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}
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/*---------------------------------------------------------------------------*/
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/** @brief Set GPIO Alternate Function Selection
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Set the alternate function mapping number for each pin. Most pins have
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alternate functions associated with them. When set to AF mode, a pin may be
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used for one of its allocated alternate functions selected by the number given
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here. To determine the number to be used for the desired function refer to the
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individual datasheet for the particular device. A table is given under the Pin
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Selection chapter.
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Note that a number of pins may be set but only with a single AF number. In
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practice this would rarely be useful as each pin is likely to require a
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different number.
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@param[in] gpioport Unsigned int32. Port identifier @ref gpio_port_id
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@param[in] alt_func_num Unsigned int8. Pin alternate function number @ref
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gpio_af_num
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@param[in] gpios Unsigned int16. Pin identifiers @ref gpio_pin_id
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If multiple pins are to be set, use bitwise OR '|' to separate
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them.
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*/
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void gpio_set_af(uint32_t gpioport, uint8_t alt_func_num, uint16_t gpios)
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{
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uint16_t i;
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uint32_t afrl, afrh;
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afrl = GPIO_AFRL(gpioport);
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afrh = GPIO_AFRH(gpioport);
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for (i = 0; i < 8; i++) {
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if (!((1 << i) & gpios)) {
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continue;
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}
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afrl &= ~GPIO_AFR_MASK(i);
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afrl |= GPIO_AFR(i, alt_func_num);
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}
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for (i = 8; i < 16; i++) {
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if (!((1 << i) & gpios)) {
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continue;
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}
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afrh &= ~GPIO_AFR_MASK(i - 8);
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afrh |= GPIO_AFR(i - 8, alt_func_num);
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}
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GPIO_AFRL(gpioport) = afrl;
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GPIO_AFRH(gpioport) = afrh;
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}
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/**@}*/
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