Difference between revisions of "SparkFun: ITG-3200,Triple-Axis Gyro"
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<pre> | <pre> | ||
− | / | + | /* |
− | + | * MiniProject02.c | |
− | + | * | |
− | + | * Created on: Sep 20, 2012 | |
− | + | * Author: Ruffin White | |
− | + | */ | |
− | |||
− | |||
− | |||
− | |||
+ | #include "Header.h" | ||
#include <stdio.h> | #include <stdio.h> | ||
#include <stdlib.h> | #include <stdlib.h> | ||
+ | #include <string.h> | ||
+ | #include <unistd.h> | ||
+ | #include <fcntl.h> | ||
+ | #include <poll.h> | ||
#include <signal.h> | #include <signal.h> | ||
− | #include | + | #include "ITG-3200.h" |
− | + | int loop=1; | |
− | |||
− | |||
− | |||
void signal_handler(int sig) | void signal_handler(int sig) | ||
{ | { | ||
printf( "Ctrl-C pressed, cleaning up and exiting..\n" ); | printf( "Ctrl-C pressed, cleaning up and exiting..\n" ); | ||
− | + | loop = 0; | |
} | } | ||
− | + | int main(int argc, char** argv){ | |
− | + | ||
− | * | + | //variable declarations |
− | + | struct pollfd fdset[1]; | |
− | + | int nfds = 1; | |
− | + | int timeout = 100; | |
− | + | int rc; | |
− | + | char* buf[MAX_BUF]; | |
− | + | int gpio1, gpio2; | |
− | + | int gpio1_fd, gpio2_fd; | |
+ | int gpio2_value = 0; | ||
+ | int pattern =0; | ||
+ | int value =0; | ||
+ | |||
+ | int freq = 10; | ||
+ | int duty = 25; | ||
+ | |||
+ | int gyroID, gyroTemp, gyroX, gyroY, gyroZ; | ||
+ | |||
+ | // I2C Variables | ||
+ | char *end; | ||
+ | int res, i2cbus, address, size, file; | ||
+ | int daddress; | ||
− | if ( | + | //check that at least two arguments are passed in |
− | printf(" | + | if(argc < 4){ |
− | + | printf("Usage: %s <input-gpio> <output-gpio> <i2c-bus>\n", argv[0]); | |
+ | printf("polls input-gpio, and writes value to output-gpio\n"); | ||
+ | fflush(stdout); | ||
+ | return 1; | ||
} | } | ||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | + | //set signal handler for Ctrl + C | |
− | } | + | if (signal(SIGINT, signal_handler) == SIG_ERR) |
+ | printf("\ncan't catch SIGINT\n"); | ||
+ | |||
+ | //assign gpio values | ||
+ | gpio1 = atoi(argv[1]); | ||
+ | gpio2 = atoi(argv[2]); | ||
+ | |||
+ | |||
+ | //assign I2C values | ||
+ | i2cbus = atoi(argv[3]); | ||
+ | address = ITG3200_I2C_ADDRESS; | ||
+ | file = initialize(i2cbus, address); | ||
+ | |||
+ | |||
+ | |||
+ | //argument 1 will be input | ||
+ | export_gpio(gpio1); | ||
+ | set_gpio_direction(gpio1, "in"); | ||
+ | set_gpio_edge(gpio1, "falling"); | ||
+ | gpio1_fd = gpio_fd_open(gpio1); | ||
+ | |||
+ | //argument 2 will be output | ||
+ | export_gpio(gpio2); | ||
+ | set_gpio_direction(gpio2, "out"); | ||
+ | set_gpio_value(gpio2, gpio2_value); | ||
+ | gpio2_fd = gpio_fd_open(gpio2); | ||
+ | |||
+ | set_mux_value("gpmc_a2",6); | ||
+ | |||
+ | |||
+ | while(loop){ | ||
+ | memset((void*)fdset, 0, sizeof(fdset)); | ||
+ | |||
+ | fdset[0].fd = gpio1_fd; | ||
+ | fdset[0].events = POLLPRI; | ||
+ | |||
+ | rc = poll(fdset, nfds, timeout); | ||
+ | |||
+ | if (rc < 0){ | ||
+ | printf("\npoll() failed!\n"); | ||
+ | } | ||
+ | |||
+ | if (rc == 0){ | ||
+ | printf("."); | ||
+ | } | ||
+ | |||
+ | if((fdset[0].revents & POLLPRI) == POLLPRI) { | ||
+ | read(fdset[0].fd, buf, MAX_BUF); | ||
+ | printf("interrupt value=%c\n", buf[0]); | ||
+ | pattern++; | ||
+ | if(pattern == 4){ | ||
+ | pattern = 0; | ||
+ | } | ||
+ | } | ||
+ | |||
+ | switch(pattern){ | ||
+ | |||
+ | // blink led | ||
+ | case 0: | ||
+ | printf("Case 0\n"); | ||
+ | value = read_ain("ain6"); | ||
+ | printf("Voltage: %d\n",value); | ||
+ | set_pwm("ehrpwm.1:0",10,25); | ||
+ | if(gpio2_value){ | ||
+ | gpio2_value = 0; | ||
+ | } | ||
+ | else{ | ||
+ | gpio2_value = 1; | ||
+ | } | ||
+ | set_gpio_value(gpio2, gpio2_value); | ||
+ | break; | ||
+ | |||
+ | //PWM output | ||
+ | case 1: | ||
+ | |||
+ | gyroID = readWhoAmI(file); | ||
+ | |||
+ | printf("gyroID: 0x%02x (%d)\n", gyroID, gyroID); | ||
+ | break; | ||
+ | |||
+ | //Read Gyro Temperature | ||
+ | case 2: | ||
+ | printf("Case 2\n"); | ||
+ | |||
+ | gyroTemp = readTemp(file); | ||
+ | |||
+ | printf("gyroTemp: 0x%02x (%d)\n", gyroTemp, gyroTemp); | ||
+ | break; | ||
+ | |||
+ | //Read Gyro XYZ | ||
+ | case 3: | ||
+ | printf("Case 3\n"); | ||
− | + | gyroX = readX(file); | |
− | + | gyroY = readY(file); | |
+ | gyroZ = readZ(file); | ||
− | + | printf("gyroX: 0x%02x (%d)\n", gyroX, gyroX); | |
− | + | printf("gyroY: 0x%02x (%d)\n", gyroY, gyroY); | |
− | + | printf("gyroZ: 0x%02x (%d)\n", gyroZ, gyroZ); | |
− | + | break; | |
− | |||
− | |||
− | + | default: | |
− | + | break; | |
− | + | } | |
− | + | } | |
− | + | close(file); | |
− | + | gpio_fd_close(gpio1_fd); | |
+ | gpio_fd_close(gpio2_fd); | ||
+ | unexport_gpio(gpio1); | ||
+ | unexport_gpio(gpio2); | ||
+ | fflush(stdout); | ||
+ | return 0; | ||
} | } | ||
+ | |||
</pre> | </pre> | ||
This code can be compiled with the command ''gcc adxl335.c -o adxl335'' | This code can be compiled with the command ''gcc adxl335.c -o adxl335'' | ||
− | |||
== Features == | == Features == |
Revision as of 08:53, 25 September 2012
Contents
Overview
The ADXL335 is a three-axis accelerometer that can be purchased from SparkFun. The datasheet describes it:
The ITG-3200 is the world’s first single-chip, digital-output, 3-axis MEMS gyro IC optimized for gaming, 3D mice, and 3D remote control applications. The part features enhanced bias and sensitivity temperature stability, reducing the need for user calibration. Low frequency noise is lower than previous generation devices, simplifying application development and making for more-responsive remote controls.
Inputs and Outputs
The ITG-3200 takes a supply voltage (Vs) of 1.8-3.6 V. The analog outputs are scaled proportionally to the supply voltage; at Vs = 3.6 V, the output will change by 2x for the same acceleration as compared to Vs = 1.8 V. Although the output sensitivity is scaled proportionally to the input voltage, noise is not, so higher supply voltages are advisable to reduce the impact of noise.
At all supply voltages, 0 g acceleration corresponds to an output voltage of Vs/2. At Vs = 3.6 V, the datasheet specs the typical sensitivity at 360 mV / g, with g as standard gravitational acceleration.
Bone Usage
Because the ITG-3200 has and I2C port, data can be read into the Bone via the I2C buss pins. One sets of I2C buss pins are required, for the X, Y, Z, and temperature outputs on the gyro. Here we will use the ITG300.h (This header also imports the i2c-dev.h and errno.h automatically, these are necessary to poll the device later on). See the picture on the right for an example wiring configuration.
"
"
Note: There are two unpopulated resistors on the I2C lines, these can be added later by the customer if desired..
Sample C Code
The code shown below is sample code to demonstrate reading analog output from the ADXL335.
/* * MiniProject02.c * * Created on: Sep 20, 2012 * Author: Ruffin White */ #include "Header.h" #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <fcntl.h> #include <poll.h> #include <signal.h> #include "ITG-3200.h" int loop=1; void signal_handler(int sig) { printf( "Ctrl-C pressed, cleaning up and exiting..\n" ); loop = 0; } int main(int argc, char** argv){ //variable declarations struct pollfd fdset[1]; int nfds = 1; int timeout = 100; int rc; char* buf[MAX_BUF]; int gpio1, gpio2; int gpio1_fd, gpio2_fd; int gpio2_value = 0; int pattern =0; int value =0; int freq = 10; int duty = 25; int gyroID, gyroTemp, gyroX, gyroY, gyroZ; // I2C Variables char *end; int res, i2cbus, address, size, file; int daddress; //check that at least two arguments are passed in if(argc < 4){ printf("Usage: %s <input-gpio> <output-gpio> <i2c-bus>\n", argv[0]); printf("polls input-gpio, and writes value to output-gpio\n"); fflush(stdout); return 1; } //set signal handler for Ctrl + C if (signal(SIGINT, signal_handler) == SIG_ERR) printf("\ncan't catch SIGINT\n"); //assign gpio values gpio1 = atoi(argv[1]); gpio2 = atoi(argv[2]); //assign I2C values i2cbus = atoi(argv[3]); address = ITG3200_I2C_ADDRESS; file = initialize(i2cbus, address); //argument 1 will be input export_gpio(gpio1); set_gpio_direction(gpio1, "in"); set_gpio_edge(gpio1, "falling"); gpio1_fd = gpio_fd_open(gpio1); //argument 2 will be output export_gpio(gpio2); set_gpio_direction(gpio2, "out"); set_gpio_value(gpio2, gpio2_value); gpio2_fd = gpio_fd_open(gpio2); set_mux_value("gpmc_a2",6); while(loop){ memset((void*)fdset, 0, sizeof(fdset)); fdset[0].fd = gpio1_fd; fdset[0].events = POLLPRI; rc = poll(fdset, nfds, timeout); if (rc < 0){ printf("\npoll() failed!\n"); } if (rc == 0){ printf("."); } if((fdset[0].revents & POLLPRI) == POLLPRI) { read(fdset[0].fd, buf, MAX_BUF); printf("interrupt value=%c\n", buf[0]); pattern++; if(pattern == 4){ pattern = 0; } } switch(pattern){ // blink led case 0: printf("Case 0\n"); value = read_ain("ain6"); printf("Voltage: %d\n",value); set_pwm("ehrpwm.1:0",10,25); if(gpio2_value){ gpio2_value = 0; } else{ gpio2_value = 1; } set_gpio_value(gpio2, gpio2_value); break; //PWM output case 1: gyroID = readWhoAmI(file); printf("gyroID: 0x%02x (%d)\n", gyroID, gyroID); break; //Read Gyro Temperature case 2: printf("Case 2\n"); gyroTemp = readTemp(file); printf("gyroTemp: 0x%02x (%d)\n", gyroTemp, gyroTemp); break; //Read Gyro XYZ case 3: printf("Case 3\n"); gyroX = readX(file); gyroY = readY(file); gyroZ = readZ(file); printf("gyroX: 0x%02x (%d)\n", gyroX, gyroX); printf("gyroY: 0x%02x (%d)\n", gyroY, gyroY); printf("gyroZ: 0x%02x (%d)\n", gyroZ, gyroZ); break; default: break; } } close(file); gpio_fd_close(gpio1_fd); gpio_fd_close(gpio2_fd); unexport_gpio(gpio1); unexport_gpio(gpio2); fflush(stdout); return 0; }
This code can be compiled with the command gcc adxl335.c -o adxl335
Features
Digital-output X-, Y-, and Z-Axis angular rate sensors (gyros) on one integrated circuit Digitally-programmable low-pass filter Low 6.5mA operating current consumption for long battery life Wide VDD supply voltage range of 2.1V to 3.6V Standby current: 5μA Digital-output temperature sensor Fast Mode I2C (400kHz) serial interface Optional external clock inputs of 32.768kHz or 19.2MHz to synchronize with system clock Pins broken out to a breadboard friendly 7-pin 0.1" pitch header
Dimensions
0.70 x 0.55" (17.78 x 13.97mm)