root@raspberrypi2 ~/projects/interrupt_test # ls -l /sys/class/gpio/gpio25/
total 0
-rw-r--r-- 1 root root 4096 Apr  8 23:56 active_low
-rw-r--r-- 1 root root 4096 Apr  8 22:29 direction
-rw-r--r-- 1 root root 4096 Apr  8 22:29 edge
drwxr-xr-x 2 root root    0 Apr  8 23:56 power
lrwxrwxrwx 1 root root    0 Apr  8 23:56 subsystem -> ../../../../class/gpio
-rw-r--r-- 1 root root 4096 Apr  8 22:08 uevent
-rw-r--r-- 1 root root 4096 Apr  8 22:29 value
root@raspberrypi2 ~/projects/interrupt_test # 

mkdir /mnt/backup
mount -t cifs //mybooklive/Public/Backup /mnt/backup -o guest

root@raspberrypi2 ~/bin # fdisk -l

Disk /dev/mmcblk0: 1973 MB, 1973420032 bytes, 3854336 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0004f23a

        Device Boot      Start         End      Blocks   Id  System
/dev/mmcblk0p1   *        2048      186367       92160    c  W95 FAT32 (LBA)
/dev/mmcblk0p2          186368     3667967     1740800   83  Linux

Disk /dev/sda: 2107 MB, 2107637760 bytes, 4116480 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

root@raspberrypi2 ~/projects/spi_test # ls -la /dev/spi*
crw------- 1 root root 153, 0 Jan  1  1970 /dev/spidev0.0
crw------- 1 root root 153, 1 Jan  1  1970 /dev/spidev0.1

package counter

import (
	"encoding/base64"
	"fmt"
	"time"
	"net/http"

	"appengine"
	"appengine/channel"
)

var GIF []byte

const (
	TOPIC = "counter"
)

func init() {
	GIF, _ = base64.StdEncoding.DecodeString("R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7")
	
	
	http.HandleFunc("/beacon.gif", handler)
	http.HandleFunc("/new_token", handler_new_token)	
}

func handler(w http.ResponseWriter, r *http.Request) {
	context := appengine.NewContext(r)

	now := time.Now()
	expire := now.AddDate(30, 0, 0)
	zcookie, _ := r.Cookie("z")
	if zcookie == nil {
		zcookie = &http.Cookie{}
		zcookie.Name = "z"
		zcookie.Value = make_hash("<your_salt>", r.RemoteAddr, now.UnixNano())
		zcookie.Expires = expire
		zcookie.Path = "/"
		http.SetCookie(w, zcookie)
	}

	w.Header().Set("Content-type", "image/gif")
	w.Header().Set("Cache-control", "no-cache, must-revalidate")
	w.Header().Set("Expires", "Sat, 26 Jul 1997 05:00:00 GMT")

	fmt.Fprintf(w, "%s", GIF)

	channel.Send(context, TOPIC, zcookie.Value+"\n"+r.RemoteAddr+"\n"+r.Referer()+"\n"+r.UserAgent())
}

func handler_new_token(w http.ResponseWriter, r *http.Request) {
	c := appengine.NewContext(r)
	tok, err := channel.Create(c, TOPIC)	
	callback := r.FormValue("callback")	
	if err != nil {
		http.Error(w, "Couldn't create Channel", http.StatusInternalServerError)
		c.Errorf("channel.Create: %v", err)
		return
	}
	if callback == "" {
		w.Header().Set("Content-type", "text/javascript")
		fmt.Fprintf(w, "%s", tok)
	} else {
		fmt.Fprintf(w, callback+"('%s')", tok)
	}
}

/*
  Blink
  Turns on an LED on for one second, then off for one second, repeatedly.
 
  This example code is in the public domain.
 */
 
// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int led = 13;

// the setup routine runs once when you press reset:
void setup() {                
  // initialize the digital pin as an output.
  pinMode(led, OUTPUT);     
}

// the loop routine runs over and over again forever:
void loop() {
  digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);               // wait for a second
  digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);               // wait for a second
}

CPU核
  |
  V
寄存器
  |
  V
执行单元 -> Load/Store缓冲区->L1 Cache --->L3 Cache-->内存控制器-->主存
       |                                   |
       +-> Write Combine缓冲区->L2 Cache ---+

private volatile long sequence = RingBuffer.INITIAL_CURSOR_VALUE;
 
// from inside the run() method
 
T event = null;
long nextSequence = sequence.get() + 1L;
while (running)
{
    try
    {
        final long availableSequence = barrier.waitFor(nextSequence);
 
        while (nextSequence <= availableSequence)
        {
            event = ringBuffer.get(nextSequence);
            boolean endOfBatch = nextSequence == availableSequence;
            eventHandler.onEvent(event, nextSequence, endOfBatch);
            nextSequence++;
        }
 
        sequence.set(nextSequence - 1L); 
        // store barrier inserted here !!!
    }
    catch (final Exception ex)
    {
        exceptionHandler.handle(ex, nextSequence, event);
        sequence.set(nextSequence);
        // store barrier inserted here !!!
        nextSequence++;
    }
}

curl -s "http://online.cnzz.com/online/online.php?id=[your_cnzz_id]&h=[your_cnzz_server_id].cnzz.com&on=1&s=line" | sed -e 's/.*当前在线\[\([0-9]\).*/\1/g'

#!/usr/bin/python

#
# based on code from lrvick and LiquidCrystal
# lrvic - https://github.com/lrvick/raspi-hd44780/blob/master/hd44780.py
# LiquidCrystal - https://github.com/arduino/Arduino/blob/master/libraries/LiquidCrystal/LiquidCrystal.cpp
#

from time import sleep
from datetime import datetime
from time import sleep

class Adafruit_CharLCD:

    # commands
    LCD_CLEARDISPLAY 		= 0x01
    LCD_RETURNHOME 		    = 0x02
    LCD_ENTRYMODESET 		= 0x04
    LCD_DISPLAYCONTROL 		= 0x08
    LCD_CURSORSHIFT 		= 0x10
    LCD_FUNCTIONSET 		= 0x20
    LCD_SETCGRAMADDR 		= 0x40
    LCD_SETDDRAMADDR 		= 0x80

    # flags for display entry mode
    LCD_ENTRYRIGHT 		= 0x00
    LCD_ENTRYLEFT 		= 0x02
    LCD_ENTRYSHIFTINCREMENT 	= 0x01
    LCD_ENTRYSHIFTDECREMENT 	= 0x00

    # flags for display on/off control
    LCD_DISPLAYON 		= 0x04
    LCD_DISPLAYOFF 		= 0x00
    LCD_CURSORON 		= 0x02
    LCD_CURSOROFF 		= 0x00
    LCD_BLINKON 		= 0x01
    LCD_BLINKOFF 		= 0x00

    # flags for display/cursor shift
    LCD_DISPLAYMOVE 		= 0x08
    LCD_CURSORMOVE 		= 0x00

    # flags for display/cursor shift
    LCD_DISPLAYMOVE 		= 0x08
    LCD_CURSORMOVE 		= 0x00
    LCD_MOVERIGHT 		= 0x04
    LCD_MOVELEFT 		= 0x00

    # flags for function set
    LCD_8BITMODE 		= 0x10
    LCD_4BITMODE 		= 0x00
    LCD_2LINE 			= 0x08
    LCD_1LINE 			= 0x00
    LCD_5x10DOTS 		= 0x04
    LCD_5x8DOTS 		= 0x00



    def __init__(self, pin_rs=8, pin_e=10, pins_db=[11,12,13,15], GPIO = None):
	# Emulate the old behavior of using RPi.GPIO if we haven't been given
	# an explicit GPIO interface to use
	if not GPIO:
	    import RPi.GPIO as GPIO
        GPIO.setwarnings(False)

   	self.GPIO = GPIO
        self.pin_rs = pin_rs
        self.pin_e = pin_e
        self.pins_db = pins_db

        self.GPIO.setmode(GPIO.BOARD)
        self.GPIO.setup(self.pin_e, GPIO.OUT)
        self.GPIO.setup(self.pin_rs, GPIO.OUT)

        for pin in self.pins_db:
            self.GPIO.setup(pin, GPIO.OUT)

	self.write4bits(0x33) # initialization
	self.write4bits(0x32) # initialization
	self.write4bits(0x28) # 2 line 5x7 matrix
	self.write4bits(0x0C) # turn cursor off 0x0E to enable cursor
	self.write4bits(0x06) # shift cursor right

	self.displaycontrol = self.LCD_DISPLAYON | self.LCD_CURSOROFF | self.LCD_BLINKOFF

	self.displayfunction = self.LCD_4BITMODE | self.LCD_1LINE | self.LCD_5x8DOTS
	self.displayfunction |= self.LCD_2LINE

	""" Initialize to default text direction (for romance languages) """
	self.displaymode =  self.LCD_ENTRYLEFT | self.LCD_ENTRYSHIFTDECREMENT
	self.write4bits(self.LCD_ENTRYMODESET | self.displaymode) #  set the entry mode

        self.clear()


    def begin(self, cols, lines):

	if (lines > 1):
		self.numlines = lines
    		self.displayfunction |= self.LCD_2LINE
		self.currline = 0


    def home(self):

	self.write4bits(self.LCD_RETURNHOME) # set cursor position to zero
	self.delayMicroseconds(3000) # this command takes a long time!
	

    def clear(self):

	self.write4bits(self.LCD_CLEARDISPLAY) # command to clear display
	self.delayMicroseconds(3000)	# 3000 microsecond sleep, clearing the display takes a long time


    def setCursor(self, col, row):

	self.row_offsets = [ 0x00, 0x40, 0x14, 0x54 ]

	if ( row > self.numlines ): 
		row = self.numlines - 1 # we count rows starting w/0

	self.write4bits(self.LCD_SETDDRAMADDR | (col + self.row_offsets[row]))


    def noDisplay(self): 
	""" Turn the display off (quickly) """

	self.displaycontrol &= ~self.LCD_DISPLAYON
	self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)


    def display(self):
	""" Turn the display on (quickly) """

	self.displaycontrol |= self.LCD_DISPLAYON
	self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)


    def noCursor(self):
	""" Turns the underline cursor on/off """

	self.displaycontrol &= ~self.LCD_CURSORON
	self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)


    def cursor(self):
	""" Cursor On """

	self.displaycontrol |= self.LCD_CURSORON
	self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)


    def noBlink(self):
	""" Turn on and off the blinking cursor """

	self.displaycontrol &= ~self.LCD_BLINKON
	self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)


    def noBlink(self):
	""" Turn on and off the blinking cursor """

	self.displaycontrol &= ~self.LCD_BLINKON
	self.write4bits(self.LCD_DISPLAYCONTROL | self.displaycontrol)


    def DisplayLeft(self):
	""" These commands scroll the display without changing the RAM """

	self.write4bits(self.LCD_CURSORSHIFT | self.LCD_DISPLAYMOVE | self.LCD_MOVELEFT)


    def scrollDisplayRight(self):
	""" These commands scroll the display without changing the RAM """

	self.write4bits(self.LCD_CURSORSHIFT | self.LCD_DISPLAYMOVE | self.LCD_MOVERIGHT);


    def leftToRight(self):
	""" This is for text that flows Left to Right """

	self.displaymode |= self.LCD_ENTRYLEFT
	self.write4bits(self.LCD_ENTRYMODESET | self.displaymode);


    def rightToLeft(self):
	""" This is for text that flows Right to Left """
	self.displaymode &= ~self.LCD_ENTRYLEFT
	self.write4bits(self.LCD_ENTRYMODESET | self.displaymode)


    def autoscroll(self):
	""" This will 'right justify' text from the cursor """

	self.displaymode |= self.LCD_ENTRYSHIFTINCREMENT
	self.write4bits(self.LCD_ENTRYMODESET | self.displaymode)


    def noAutoscroll(self): 
	""" This will 'left justify' text from the cursor """

	self.displaymode &= ~self.LCD_ENTRYSHIFTINCREMENT
	self.write4bits(self.LCD_ENTRYMODESET | self.displaymode)


    def write4bits(self, bits, char_mode=False):
        """ Send command to LCD """

	self.delayMicroseconds(1000) # 1000 microsecond sleep

        bits=bin(bits)[2:].zfill(8)

        self.GPIO.output(self.pin_rs, char_mode)

        for pin in self.pins_db:
            self.GPIO.output(pin, False)

        for i in range(4):
            if bits[i] == "1":
                self.GPIO.output(self.pins_db[::-1][i], True)

	self.pulseEnable()

        for pin in self.pins_db:
            self.GPIO.output(pin, False)

        for i in range(4,8):
            if bits[i] == "1":
                self.GPIO.output(self.pins_db[::-1][i-4], True)

	self.pulseEnable()


    def delayMicroseconds(self, microseconds):
	seconds = microseconds / float(1000000)	# divide microseconds by 1 million for seconds
	sleep(seconds)


    def pulseEnable(self):
	self.GPIO.output(self.pin_e, False)
	self.delayMicroseconds(1)		# 1 microsecond pause - enable pulse must be > 450ns 
	self.GPIO.output(self.pin_e, True)
	self.delayMicroseconds(1)		# 1 microsecond pause - enable pulse must be > 450ns 
	self.GPIO.output(self.pin_e, False)
	self.delayMicroseconds(1)		# commands need > 37us to settle


    def message(self, text):
        """ Send string to LCD. Newline wraps to second line"""

        for char in text:
            if char == '\n':
                self.write4bits(0xC0) # next line
            else:
                self.write4bits(ord(char),True)


if __name__ == '__main__':

    lcd = Adafruit_CharLCD()
    lcd.noBlink()

    while True:
        sleep(1)
        lcd.clear()        
        lcd.message(datetime.now().strftime('  %I : %M : %S \n%a %b %d %Y'))