Raspberry

Da comPVter Wiki.
Jump to navigation Jump to search

Dopo aver installato Raspbian e collegato una vecchia televisione, l'immagine risulta spostata a sinistra. Per corregere il posizionamento verticale ho effettuato la seguente modifica alla configurazione: 

vi /boot/config.txt (sudo)

Modificare la seguente riga 

overscan_left=26
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

Ora che riesco a digitare comandi e visualizzare il loro output procedo con l'installazione. Attivo interfaccia grafica 

startx

Collego alla rete wifi, la chiavetta Dlink è riconosciuta automaticamente e basta quindi inserire la PSK.

A questo punto installo xrdp, al fine di collegarmi da un PC windows, la vecchia tele PAL non ha una grafica entusiasmante. 

apt-get update
apt-get install xrdp

Prossimo obiettivo far funzionare un vecchio monitor con ingresso DVI-D (cavo 2,80€) 

hdmi_safe=1

Obiettivo raggiunto, ma la risoluzione usata è a dir poco deludente (pisquana).

Tolgo un po di bordo 

overscan_left=0
overscan_right=0
overscan_top=0
overscan_bottom=0

Rimuovo la modalità safe e forzo il riconoscimento 

hdmi_safe=1
hdmi_force_hotplug=1

Ora imposto la risoluzione che meglio si adatta al monitor 

hdmi_group=2
hdmi_mode=16
(hdmi_mode=16   1024x768  60Hz)


Le specifiche si trovano seguendo il link [1]


Ora passiamo all'installazione di "Quake". Seguo le istruzioni da link [2] Installiamo il compilatore (speriamo basti lo spazio sulla SD 

sudo apt-get install git gcc build-essential libsdl1.2-dev

Controlliamo 

df -h

Filesystem      Size  Used Avail Use% Mounted on
rootfs          1.8G  1.4G  311M  82% /
/dev/root       1.8G  1.4G  311M  82% /
devtmpfs         93M     0   93M   0% /dev
tmpfs            19M  256K   19M   2% /run
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs            37M     0   37M   0% /run/shm
/dev/mmcblk0p1   56M   17M   40M  30% /boot

Scarichiamo i sorgenti 

git clone https://github.com/raspberrypi/quake3.git

Modificare il percorso delle LIB 

cd quake3
vi build.sh
ARM_LIBS=/opt/vc/lib

Modificare gli INCLUDE 

INCLUDES="-I/opt/vc/include -I/opt/vc/include/interface/vcos/pthreads"

Nessun cross compilatore 

#CROSS_COMPILE=bcm2708-

Ora si compila 

./build.sh

Scarichiamo il Demo Park 

pi@raspberrypi ~ $ wget http://dl.dropbox.com/u/1816557/Q3%20Demo%20Paks.zip
--2012-12-02 16:36:41--  http://dl.dropbox.com/u/1816557/Q3%20Demo%20Paks.zip
Resolving dl.dropbox.com (dl.dropbox.com)... 174.129.253.24, 184.73.171.217, 50.16.240.166, ...
Connecting to dl.dropbox.com (dl.dropbox.com)|174.129.253.24|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 72084355 (69M) [application/zip]
Saving to: `Q3 Demo Paks.zip'

100%[===================================================================================>] 72,084,355   326K/s   in 8m 20s
2012-12-02 16:45:04 (141 KB/s) - `Q3 Demo Paks.zip' saved [72084355/72084355]

Ora rimane proprio poco spazio. Inoltre sono più di 20 minuti che sta compilando, speriamo non fonda. Ora ha finito, ci ha messo circa 1 ora.

Ora salvo immagine SD e allargo la partizione di root.

Per allargare la partizione di root 

sudo raspi-config

Quindi si seleziona 

expand_rootfs

Si riavvia e si attende che il lavoro sia finito. Ecco il risultato 

Filesystem      Size  Used Avail Use% Mounted on
rootfs          7.3G  1.6G  5.4G  22% /
/dev/root       7.3G  1.6G  5.4G  22% /
devtmpfs         93M     0   93M   0% /dev
tmpfs            19M  252K   19M   2% /run
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs            37M     0   37M   0% /run/shm
/dev/mmcblk0p1   56M   17M   40M  30% /boot


Interfacciamaento con I2c a MPU6050

Modificare 

vi /etc/modprobe.d/raspi-blacklist.conf

#blacklist i2c-bcm2708

Quindi un reboot 

modprobe i2c-dev
ls /dev/i2c*



ls -la /dev/i2c*
crw------- 1 root root 89, 0 Dec  3 15:35 /dev/i2c-0
crw------- 1 root root 89, 1 Dec  3 15:35 /dev/i2c-1

chmod o+rw /dev/i2c*

ls -la /dev/i2c*

crw----rw- 1 root root 89, 0 Dec  3 15:35 /dev/i2c-0
crw----rw- 1 root root 89, 1 Dec  3 15:35 /dev/i2c-1

Installiamo ora gli i2c-tools 

apt-get -y install git i2c-tools

Verificare che veda il dispositivo su bus i2c sul bus 0 nel mio caso 

i2cdetect 0

WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-0.
I will probe address range 0x03-0x77.
Continue? [Y/n] y
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- 68 -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --


Rilevato dispositivo all'indirizzo 0x68 (MPU6050) Documentazione: [3] [4]


Ora preparo un programma mio, prendendo spunto dalla rete. 

#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>
void ReadTemperatura(int);
unsigned int ReadW(int , unsigned char );
unsigned char  ReadB(int , unsigned char );
void InitMpu6050(int);
//**** Global
int  address = 0x68;

int main(int argc, char **argv)
{
	printf("**** MPU6050 test program ****\n");
	
	int fd;														// File descrition
	int result;
	char *fileName = "/dev/i2c-0";								// Name of the port we will be using
	unsigned char buf[10];										// Buffer for data being read/ written on the i2c bus
	
	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);
	}

	InitMpu6050(fd);
	//ReadTemperatura(fd);
	result = ReadW(fd,0x3b);
	double dT = ( (double) result + 12412.0) / 340.0;
	printf("Temp as decimal: %f\n",dT); // display bearing with decimal place
	
	result = ReadW(fd,0x3b);
	printf("Ax as decimal: %u\n",result); // display Acc X
	result = ReadW(fd,0x3d);
	printf("Ay as decimal: %u\n",result); // display Acc Y
	result = ReadW(fd,0x3f);
	printf("Az as decimal: %u\n",result); // display Acc Z


	result = ReadW(fd,0x43);
	printf("Gx as decimal: %u\n",result); // display Gyro X
	result = ReadW(fd,0x45);
	printf("Gy as decimal: %u\n",result); // display Gyro Y
	result = ReadW(fd,0x47);
	printf("Gz as decimal: %u\n",result); // display Gyro Z

	
	return 0;
}

void InitMpu6050(int fd_mpu6050)
{
	unsigned char buf[10];										// Buffer for data being read/ written on the i2c bus

	if (ioctl(fd_mpu6050, 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] = 0x41;													// This is the register we want to read from
	if ((write(fd_mpu6050, buf, 1)) != 1) {								// Send register we want to read from	
		printf("Error writing to i2c slave\n");
		exit(1);
	}

}
void ReadTemperatura(int fd_mpu6050)
{
	unsigned char buf[10];										// Buffer for data being read/ written on the i2c bus
	buf[0] = 0x41;													// This is the register we want to read from
	
	if ((write(fd_mpu6050, buf, 1)) != 1) {								// Send register we want to read from	
		printf("Error writing to i2c slave\n");
		exit(1);
	}
	
	if (read(fd_mpu6050, buf, 2) != 2) {								// Read back data into buf[]
		printf("Unable to read from slave\n");
		exit(1);
	}
	else {
		unsigned char highByte = buf[0];
		unsigned char lowByte = buf[1];
		unsigned int result = (highByte <<8) + lowByte;			// Calculate bearing as a word value
		double dT = ( (double) result + 12412.0) / 340.0;
		printf("Temp as decimal: %f\n",dT); // display bearing with decimal place
	}
	

}

unsigned int  ReadW(int fd_mpu6050, unsigned char addr)
{
	unsigned char buf[10];										// Buffer for data being read/ written on the i2c bus
	unsigned int result;
	
	buf[0] = addr;													// This is the register we want to read from
	
	if ((write(fd_mpu6050, buf, 1)) != 1) {								// Send register we want to read from	
		printf("Error writing to i2c slave\n");
		exit(1);
	}
	
	if (read(fd_mpu6050, buf, 2) != 2) {								// Read back data into buf[]
		printf("Unable to read from slave\n");
		exit(1);
	}
	else {
		unsigned char highByte = buf[0];
		unsigned char lowByte = buf[1];
		result = (highByte <<8) + lowByte;			// Calculate bearing as a word value
	}
	return result;

}

unsigned char  ReadB(int fd_mpu6050, unsigned char addr)
{
	unsigned char buf[10];										// Buffer for data being read/ written on the i2c bus
	unsigned char result;
	
	buf[0] = addr;													// This is the register we want to read from
	
	if ((write(fd_mpu6050, buf, 1)) != 1) {								// Send register we want to read from	
		printf("Error writing to i2c slave\n");
		exit(1);
	}
	
	if (read(fd_mpu6050, buf, 1) != 1) {								// Read back data into buf[]
		printf("Unable to read from slave\n");
		exit(1);
	}
	else {
		result = buf[0];
	}
	return result;

}

Poi ne compilo uno bello, fatto da qualcuno che ha tempo per programmare.

Estratto da "http://www.compvter.org/index.php?title=Raspberry&oldid=8232"