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vf6xx: add GPIO example

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This example muxes two pins as GPIO and enables one GPIO (logical
high). The other GPIO is then read in the main loop. One can use
a jumper to bridge the two GPIOs to see that also reading succeeds.
This commit is contained in:
Stefan Agner
2014-07-09 23:59:57 +02:00
committed by Karl Palsson
parent 0b9e7d0d5d
commit 1123768e78
2 changed files with 121 additions and 0 deletions
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26
examples/vf6xx/colibri-vf61/gpio/Makefile Normal file
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##
## This file is part of the libopencm3 project.
##
## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
## Copyright (C) 2014 Stefan Agner <stefan@agner.ch>
##
## This library is free software: you can redistribute it and/or modify
## it under the terms of the GNU Lesser General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## This library 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 Lesser General Public License for more details.
##
## You should have received a copy of the GNU Lesser General Public License
## along with this library. If not, see <http://www.gnu.org/licenses/>.
##
BINARY = gpio
LDSCRIPT = ../colibri-vf61.ld
include ../Makefile.include

95
examples/vf6xx/colibri-vf61/gpio/gpio.c Normal file
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/*
* This file is part of the libopencm3 project.
*
* Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
* Copyright (C) 2014 Stefan Agner <stefan@agner.ch>
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <errno.h>
#include <libopencm3/cm3/common.h>
#include <libopencm3/vf6xx/ccm.h>
#include <libopencm3/vf6xx/uart.h>
#include <libopencm3/vf6xx/gpio.h>
#include <libopencm3/vf6xx/iomuxc.h>
static const uint32_t gpio_out = IOMUXC_PAD(MUX_MODE_ALT0, SPEED_LOW, \
DSE_150OHM, PUS_PU_100KOHM, IOMUXC_OBE | IOMUXC_IBE);
static const uint32_t gpio_in = IOMUXC_PAD(MUX_MODE_ALT0, SPEED_LOW, \
DSE_150OHM, PUS_PU_100KOHM, IOMUXC_IBE);
int _write(int file, char *ptr, int len);
void sys_tick_handler(void);
int _write(int file, char *ptr, int len)
{
int i;
if (file == 1) {
for (i = 0; i < len; i++)
uart_send_blocking(UART2, ptr[i]);
return i;
}
errno = EIO;
return -1;
}
static void uart_init()
{
ccm_clock_gate_enable(CG9_UART2);
uart_enable(UART2);
uart_set_baudrate(UART2, 115200);
}
int main(void)
{
int old_state = -1;
int new_state = 0;
/* Init Clock Control and UART */
ccm_calculate_clocks();
uart_init();
/* Iris Carrier Board, X16, Pin 15 */
iomuxc_mux(PTC3, gpio_out);
/* Iris Carrier Board, X16, Pin 16 */
iomuxc_mux(PTC2, gpio_in);
gpio_set(PTC3);
printf("GPIO %d is %s\r\n", PTC3, gpio_get(PTC3) ? "high" : "low");
/*
* Read input GPIO in a loop and print changes
* A jumper between PTC3<=> PTC2 can be used to set PTC2 to high
*/
while (1) {
new_state = gpio_get(PTC2);
if (old_state != new_state) {
printf("GPIO %d is %s\r\n", PTC2,
new_state ? "high" : "low");
old_state = new_state;
}
}
return 0;
}