아두이노랑은 이렇게 하라는데
일단.. I2C로 할거니까.. 저렇게 위에 4개 선을 연결하면 어찌어찌 라즈베리에서도 사용가능 할 듯
장치 ID는 0xE5 고정
ADXL345
REGISTER DEFINITIONS
Register 0x00—DEVID (Read Only)
The DEVID register holds a fixed device ID code of 0xE5 (345 octal).
데이터는 X/Y/Z축 LSB / MSB 순으로 들어 있다.
Register 0x32 to Register 0x37—DATAX0, DATAX1,
DATAY0, DATAY1, DATAZ0, DATAZ1 (Read Only)
These six bytes (Register 0x32 to Register 0x37) are eight bits
each and hold the output data for each axis. Register 0x32 and
Register 0x33 hold the output data for the x-axis, Register 0x34 and
Register 0x35 hold the output data for the y-axis, and Register 0x36
and Register 0x37 hold the output data for the z-axis. The output
data is twos complement, with DATAx0 as the least significant
byte and DATAx1 as the most significant byte, where x represent X,
Y, or Z. The DATA_FORMAT register (Address 0x31) controls
the format of the data. It is recommended that a multiple-byte
read of all registers be performed to prevent a change in data
between reads of sequential registers
I 2
C
With CS tied high to VDD I/O, the ADXL345 is in I2
C mode,
requiring a simple 2-wire connection, as shown in Figure 40.
The ADXL345 conforms to the UM10204 I
2
C-Bus Specification
and User Manual, Rev. 03—19 June 2007, available from NXP
Semiconductors. It supports standard (100 kHz) and fast (400 kHz)
data transfer modes if the bus parameters given in Table 11
and Table 12 are met. Single- or multiple-byte reads/writes are
supported, as shown in Figure 41. With the ALT ADDRESS pin
high, the 7-bit I
2
C address for the device is 0x1D, followed by
the R/W bit. This translates to 0x3A for a write and 0x3B for a
read. An alternate I2
C address of 0x53 (followed by the R/W bit)
can be chosen by grounding the ALT ADDRESS pin (Pin 12).
This translates to 0xA6 for a write and 0xA7 for a read.
There are no internal pull-up or pull-down resistors for any
unused pins; therefore, there is no known state or default state
for the CS or ALT ADDRESS pin if left floating or unconnected.
It is required that the CS pin be connected to VDD I/O and that
the ALT ADDRESS pin be connected to either VDD I/O or GND
when using I2
C
[링크 : http://eleparts.co.kr/data/design/product_file/SENSOR/G_SENSOR/data/ADXL345.pdf]
---
---
pi@raspberrypi /boot/overlays $ dmesg | grep i2c
[ 3.862054] bcm2708_i2c_init_pinmode(1,2)
[ 3.863939] bcm2708_i2c_init_pinmode(1,3)
[ 3.866020] bcm2708_i2c 3f804000.i2c: BSC1 Controller at 0x3f804000 (irq 79) (baudrate 100000)
pi@raspberrypi /boot/overlays $ lsmod | grep i2c
i2c_bcm2708 4990 0
pi@raspberrypi /boot/overlays $ insmod i2c-dev
Error: could not load module i2c-dev: No such file or directory
pi@raspberrypi /boot/overlays $ sudo vi /etc/modules
i2c-dev
i2c-bcm2708
pi@raspberrypi ~ $ lsmod | grep i2c
i2c_dev 6027 0
i2c_bcm2708 4990 0
pi@raspberrypi ~ $ i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- 53 -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
pi@raspberrypi ~ $ i2cdetect -y 0
Error: Could not open file `/dev/i2c-0' or `/dev/i2c/0': No such file or directory
pi@raspberrypi ~ $ i2cdetect -l
i2c-1 i2c 3f804000.i2c I2C adapter
pi@raspberrypi ~ $ i2cdetect -F 1
Functionalities implemented by /dev/i2c-1:
I2C yes
SMBus Quick Command yes
SMBus Send Byte yes
SMBus Receive Byte yes
SMBus Write Byte yes
SMBus Read Byte yes
SMBus Write Word yes
SMBus Read Word yes
SMBus Process Call yes
SMBus Block Write yes
SMBus Block Read no
SMBus Block Process Call no
SMBus PEC yes
I2C Block Write yes
I2C Block Read yes
pi@raspberrypi ~ $ lsmod | grep -i i2c
i2c_dev 6027 0
i2c_bcm2708 4990 0
insmod가 아니라 modprobe ...
pi@raspberrypi ~ $ sudo modprobe i2c_dev
pi@raspberrypi ~ $ lsmod | grep i2c
i2c_dev 6027 0
i2c_bcm2708 4990 0
[링크 : http://raspberrypi.stackexchange.com/.../how-to-make-raspbian-load-the-i2c-dev-module-on-boot-up]
---
#include <stdio.h> #include <stdlib.h> #include <linux/i2c-dev.h> #include <fcntl.h> #include <string.h> #include <sys/ioctl.h> #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> #include <iostream>
int main(int argc, char **argv) { printf("**** ADXL435 example program ****\n"); int fd; // File descrition char *fileName = "/dev/i2c-1"; // Name of the port we will be using int address = 0x53; // Address of the SRF02 shifted right one bit char buf[6]; // Buffer for data being read/ written on the i2c bus short x,y,z;
if ((fd = open(fileName, O_RDWR)) < 0) { // Open port for reading and writing printf("Failed to open i2c port\n"); exit(1); } if (ioctl(fd, I2C_SLAVE, address) < 0) { // Set the port options and set the address of the device we wish to speak to printf("Unable to get bus access to talk to slave\n"); exit(1); }
buf[0] = 0x2d; // Commands for performing a ranging buf[1] = 0x18; if ((write(fd, buf, 2)) != 2) { // Write commands to the i2c port printf("Error writing to i2c slave\n"); exit(1); }
buf[0] = 0x31; // Commands for performing a ranging buf[1] = 0x09; if ((write(fd, buf, 2)) != 2) { // Write commands to the i2c port printf("Error writing to i2c slave\n"); exit(1); }
// This sleep waits for the ping to come back while(true){
buf[0] = 0x32; // This is the register we wish to read from if ((write(fd, buf, 1)) != 1) { // Send the register to read from printf("Error writing to i2c slave\n"); exit(1); }
usleep(1000); memset(&buf,0,sizeof(buf));
if (read(fd, buf, 6) != 6) { // Read back data into buf[] printf("Unable to read from slave\n"); exit(1); } else { x=y=z=0; // memset(&buf,0,sizeof(buf));
x = ((short)buf[1]<<8) | (short) buf[0]; y = ((short)buf[3]<<8) | (short) buf[2]; z = ((short)buf[5]<<8) | (short) buf[4]; std::cout<<"x:"<<x<<"\ty:"<<y<<"\tz:"<<z<<std::endl; } } return 0; } |
