//I_CLK 1010101010101010101\r
//c_ff10 0011110011110011110\r
//c_ff11 0011000011000011000\r
//c_ff20 0000110000110000110\r
//c_ff21 0110000110000110000\r
//O_12M 0000110110110110110\r
//I_CLK 1010101010101010101\r
//c_ff10 0011110011110011110\r
//c_ff11 0011000011000011000\r
//c_ff20 0000110000110000110\r
//c_ff21 0110000110000110000\r
//O_12M 0000110110110110110\r