counter 310 1 similarly the n th channel checker 300 n determines whether the write channel bus is used based on the wvalid signal and the wready signal of the n th master module 200 n in so doing the n th channel checker 300 n applies an and operation 360 n _ 1 to the rvalid signal and the rready signal received from the n th master module 200 n and an and operation 360 n _ 2 to the wvalid signal and the wready signal next by applying an or operation 370 n to the and operation 360 n _ 1 of the read channel and the and operation 360 n _ 2 of the write channel the n th channel checker 300 n determines whether the n th master module 200 n uses the read channel or the write channel the n th channel checker 300 n sends the result of the or operation 370 n to an u2018 en u2019 pin of the n th counter 310 n the counters 310 1 through 310 n determine activity information of the corresponding master module according to the bus use information of the master modules 200 1 through 200 n provided from the channel checkers 300 1 through 310 n for example the counters 310 1 through 310 n count only when the master modules 200 1 through 200 n utilize the bus the counters 310 1 through 310 n send the activity information of the master modules 200 1 through 200 n accumulated for a certain time to the weight controller 320 for example the counters 310 1 through.