Xenomai:Blinking LEDs
From ArmadeusWiki
This tutorial explains how to create a simple Xenomai application. This application will blink the APF9328DevFull user LED (connected to pin 31 of i.MXL portD; on the APF27 you would use pin 14 of portF).
Contents |
Application code
$ mkdir xeno_led $ vim xeno_led/blink.c
#include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <unistd.h> #include <sys/stat.h> #include <sys/types.h> #include <sys/ioctl.h> #include <signal.h> #include <sys/mman.h> #include <native/task.h> #include <native/timer.h> #define TIMESLEEP 1000000000 /* 1 sec */ #define LED "/dev/gpio/PD31" /* APF9328 */ #define LED "/dev/gpio/PF14" /* APF27 */ RT_TASK blink_task; int fd; void blink(void *arg __attribute__((__unused__))) { int iomask = 0x00; rt_task_set_periodic(NULL, TM_NOW, TIMESLEEP); while(1) { rt_task_wait_period(NULL); write(fd,&iomask,sizeof(iomask)); iomask ^= 1; } } void catch_signal() {} int main(void) { signal(SIGTERM, catch_signal); signal(SIGINT, catch_signal); /* Avoids memory swapping for this program */ mlockall(MCL_CURRENT|MCL_FUTURE); /* led device opening */ if ((fd = open(LED, O_WRONLY)) < 0) { printf("Open error on %s\n",LED); exit(0); } /* Task Creation */ rt_task_create(&blink_task, "blinkLed", 0, 99, 0); rt_task_start(&blink_task, &blink, NULL); getchar(); rt_task_delete(&blink_task); close(fd); return 0; }
This source looks very like a classical Linux application with threads and nanosleep() function.
The only differences are on the task creation using Xenomai API:
- Create a new task with stksize stack size, prio level of priority and mode type of creation:
int rt_task_create(RT_TASK * task, const char * name, int stksize, int prio, int mode)
- Launch the new task with entry function and cookie parameters:
int rt_task_start (RT_TASK *task, void(*entry)(void *cookie), void *cookie)
- set for the task periodic, idate time for the first release (time in nanoseconds)
int rt_task_set_periodic (RT_TASK *task, RTIME idate, RTIME period)
- To block the task during the previously set period:
int rt_task_wait_period (unsigned long *overruns_r)
Makefile
The second step is to create a Makefile with specific Xenomai includes.
$ vim xeno_led/Makefile
###### CONFIGURATION ###### DEST_DIR=/tftpboot/local/bin ARMADEUS_BASE_DIR=../ include $(ARMADEUS_BASE_DIR)/Makefile.in XENO=$(ARMADEUS_ROOTFS_DIR)/usr/xenomai CC:=$(ARMADEUS_TOOLCHAIN_PATH)/arm-linux-gcc LD:=$(ARMADEUS_TOOLCHAIN_PATH)/arm-linux-ld CXX:=$(ARMADEUS_TOOLCHAIN_PATH)/arm-linux-g++ AS:=$(ARMADEUS_TOOLCHAIN_PATH)/arm-linux-as NM:=$(ARMADEUS_TOOLCHAIN_PATH)/arm-linux-nm AR:=$(ARMADEUS_TOOLCHAIN_PATH)/arm-linux-ar SIZE:=$(ARMADEUS_TOOLCHAIN_PATH)/arm-linux-size OBJCOPY:=$(ARMADEUS_TOOLCHAIN_PATH)/arm-linux-objcopy EXEC=blink_led_xeno_userspace SRC= $(wildcard *.c) OBJ= $(SRC:.c=.o) CFLAGS=-g -W -Wall -I$(XENO)/include -I$(XENO)/include/native -I$(XENO)/include/rtdm -D_GNU_SOURCE -D_REENTRANT LDFLAGS=-L$(XENO)/lib -Xlinker -rpath $(XENO)/lib -Xlinker $(XENO)/lib/libnative.a $(XENO)/lib/librtdm.a -lpthread -lnative -lrtdm $(EXEC): $(OBJ) $(CC) -o $@ $^ $(LDFLAGS) $(OBJ): $(SRC) $(CC) $(CFLAGS) -o $@ -c $< all: $(EXEC) clean: rm -rf $(OBJ) rm -rf $(EXEC) rm -f *.c~ *.h~ Makefile~ install: $(EXEC) @mkdir -p $(DEST_DIR)/$(EXEC) echo "$(EXEC):native:!./$(EXEC);popall:control_c" > $(DEST_DIR)/$(EXEC)/.runinfo cp -f $(EXEC) $(DEST_DIR)/$(EXEC) mrproper: clean rm -rf $(DEST_DIR)/$(EXEC) .PHONY: all install clean mrproper
- ARMADEUS_BASE_DIR: needs to be adapted to the correct path where the Armadeus SDK is installed, relatively to your example dir or as an absolute path.
- DEST_DIR: directory where the executables will be installed when doing make install. Here it assumes you used an NFS exported dir /tftpboot/local, mount as /usr/local on the board.
Compilation, installation and run
$ make -C xeno_led
- If you setup the NFS as indicated above, you can install the application on your board with:
$ make install -C xeno_led
- Otherwise you can install the executable to your board (through TFTP for example):
$ make install -C xeno_led/ DEST_DIR=/tftpboot
# mkdir -p /usr/local/bin/blink_led_xeno_userspace # tftp -g -r blink_led_xeno_userspace/blink_led_xeno_userspace -l /usr/local/bin/blink_led_xeno_userspace/blink_led_xeno_userspace 192.168.1.2 # tftp -g -r blink_led_xeno_userspace/.runinfo -l /usr/local/bin/blink_led_xeno_userspace/.runinfo 192.168.1.2 # chmod a+x /usr/local/bin/blink_led_xeno_userspace/blink_led_xeno_userspace
Running
- GPIO driver should be loaded:
# loadgpio.sh
- And you should be able to blink the LED from command line following these instructions
- Then, you must change directory to /usr/local/bin and type :
# xeno-load blink_led_xeno_userspace