#计算CRC16
def crc(num)
    crcnum=0xFFFF    
    num.each do|i|
        crcnum=crcnum^((i.to_i)&0x00ff)
        1.upto(8) do 
            if (crcnum&0x0001)!=0 then
                crcnum=(crcnum>>1)^0x8005
             else
                crcnum=crcnum>>1
            end
        end
    end
    return crcnum
end

#测试
#要计算的数据
dd=[20, 03, 01, 40, 00, 15]

sum= crc(dd)
#打印结果
puts "十进制:"+ sum.to_s
puts "十六进制:0x"+ sum.to_s(16)

#获取低8位
puts "0x"+ ((sum>>0)&0x00FF).to_s(16)
#获取高8位
puts "0x"+ ((sum>>8)&0x00FF).to_s(16)