require "timeout"
class Rs232c

def initialize(adrs=0, baud=9600, bit=8, parity="odd", stopbit=1, delim="\x0d\x0a")
  devname="/dev/ttyUSB%d"%adrs
  @port=open(devname,"r+")
  odd=(parity=~/o/i)
  str="%d cs%d %sparenb %sparodd %scstopb"%[baud,bit,(parity)?"":"-",(odd)?"":"-",(stopbit==2)?"":"-"]
  system("stty raw -echo -crtscts "+str+" <%s"%devname)
#  system("stty raw -echo -crtscts 9600 cs8 -parenb -parodd cstopb <%s"%devname)
# 9600, 8bit, parity, even, stop1
  @delim=delim
#  @delim="\x0d"
  each_init
end

def finish
  @port.close
end
def each_init()
  # initialization for each instrument
end

def talk(str)
  begin
  strs=str+@delim
  timeout(1){
      @port.write(strs)
      @port.flush
    }
  rescue TimeoutError
    puts "write timeout error at #{Time::now} on ttyUSB with '#{str}'"
  end
end

def echo(str)
  begin
  strs=str+@delim
  timeout(1){
      strs.split(//).each{|s|
        @port.write(s)
        @port.flush
        @port.read(1)
      }
    }
  rescue TimeoutError
    puts "write timeout error at #{Time::now} on ttyUSB with '#{str}'"
  end
end

def listen(n=256)
  begin
    timeout(2){
#	@port.readpartial(256)
      @port.gets(@delim)
    }
  rescue TimeoutError
    puts "read timeout error at #{Time::now} on ttyUSB"
    return 0
  end
end

def idn()
  talk(sprintf("*IDN?"))
  listen()
end

end #class