SONY非接触型カードリーダーRC-S380とraspberry pi（実装編）NFCを読み込んでLCDにID表示まで

#!/usr/bin/env python
# coding:UTF-8

import nfc
import binascii
import time
from threading import Thread, Timer
import smbus
import sys

# 読み取り待ち受けの1サイクル秒
TIME_cycle = 3.0
# 待ち受けの反応インターバル秒
TIME_interval = 0.2
# タッチされてから次の待ち受けを開始するまで無効化する秒
TIME_wait = 3

# NFC接続リクエストのための準備
# 212F(FeliCa)で設定
target_req_felica = nfc.clf.RemoteTarget("212F")
# 106A(NFC type A)で設定
target_req_nfc = nfc.clf.RemoteTarget("106A")

# Define some device parameters
I2C_ADDR = 0x27 # I2C device address, if any error, change this address to 0x3f
LCD_WIDTH = 16 # Maximum characters per line

# Define some device constants
LCD_CHR = 1 # Mode - Sending data
LCD_CMD = 0 # Mode - Sending command

LCD_LINE_1 = 0x80 # LCD RAM address for the 1st line
LCD_LINE_2 = 0xC0 # LCD RAM address for the 2nd line
LCD_LINE_3 = 0x94 # LCD RAM address for the 3rd line
LCD_LINE_4 = 0xD4 # LCD RAM address for the 4th line

LCD_BACKLIGHT = 0x08 # On
#LCD_BACKLIGHT = 0x00 # Off

ENABLE = 0b00000100 # Enable bit

# Timing constants
E_PULSE = 0.0005
E_DELAY = 0.0005

#Open I2C interface
#bus = smbus.SMBus(0) # Rev 1 Pi uses 0
bus = smbus.SMBus(1) # Rev 2 Pi uses 1

def lcd_init():
# Initialise display
lcd_byte(0x33,LCD_CMD) # 110011 Initialise
lcd_byte(0x32,LCD_CMD) # 110010 Initialise
lcd_byte(0x06,LCD_CMD) # 000110 Cursor move direction
lcd_byte(0x0C,LCD_CMD) # 001100 Display On,Cursor Off, Blink Off
lcd_byte(0x28,LCD_CMD) # 101000 Data length, number of lines, font size
lcd_byte(0x01,LCD_CMD) # 000001 Clear display

def lcd_byte(bits, mode):
# Send byte to data pins
# bits = the data
# mode = 1 for data
# 0 for command

bits_high = mode | (bits & 0xF0) | LCD_BACKLIGHT
bits_low = mode | ((bits<<4) & 0xF0) | LCD_BACKLIGHT

# High bits
bus.write_byte(I2C_ADDR, bits_high)
lcd_toggle_enable(bits_high)

# Low bits
bus.write_byte(I2C_ADDR, bits_low)
lcd_toggle_enable(bits_low)

def lcd_toggle_enable(bits):
# Toggle enable
time.sleep(E_DELAY)
bus.write_byte(I2C_ADDR, (bits | ENABLE))
time.sleep(E_PULSE)
bus.write_byte(I2C_ADDR,(bits & ~ENABLE))
time.sleep(E_DELAY)

def lcd_string(message,line):
# Send string to display
message = message.ljust(LCD_WIDTH," ")
lcd_byte(line, LCD_CMD)

for i in range(LCD_WIDTH):
lcd_byte(ord(message[i]),LCD_CHR)

# Main program block
def main():
# Initialise display
lcd_init()

print 'NFC waiting...'
# USBに接続されたNFCリーダに接続してインスタンス化
clf = nfc.ContactlessFrontend('usb')

while True:
target_res = clf.sense(target_req_nfc,target_req_felica, iterations=int(TIME_cycle//TIME_interval)+1 , interval=TIME_interval)

if not target_res is None:
tag = nfc.tag.activate(clf, target_res)
print 'TAG type: ' + tag.type
print str(tag.identifier).encode('hex').upper()

msg1 = str(tag.identifier).encode('hex').upper()
msg2 = "I got it!"
#LCDに表示
lcd_string(msg1,LCD_LINE_1)
lcd_string(msg2,LCD_LINE_2)

print 'sleep ' + str(TIME_wait) + ' seconds'
time.sleep(TIME_wait)
clf.close()

if __name__ == '__main__':

try:
main()
except KeyboardInterrupt:
pass
finally:
# LCD_BACKLIGHT = 0x00
lcd_byte(0x01, LCD_CMD)
sys.exit(0)