I'm not 100% familiar with the Asr but I know it also has a built in sequencer like the MPC so you will need to set it's midi clock to EXT (external)/slave or something similar.
Connect a cable from one of the MPC's MIDI out's to the IN of the Asr, make sure on the MIDI setting page on the mpc (Shift+9) that sync in is off and set Sync Out to transmit clock to your desired MIDI out port i.e. A, B or A+B, then highlight mode, scroll until it says midi clock.
Also connect a MIDI cable from the MIDI out of the asr to one input on the MPC, select a desired MIDI receive and transmit channel in the settings on the Asr.
Now press main screen in the MPC and select an empty track, highlight where it says "S:Drum1" and scroll with the data well left until it says "MIDI" then where it says "OFF" select your desired MIDI channel.
Now there may bee other settings in the asr’s MIDI settings page but read the MANUAL! Things I’m guessing like when you press play on the MP weather the sequencer on the asr will start or not and other shit like that.
Hope this helps and hope it's all correct (I still haven't read my MPC manual hahah

) but the thing is just so easy to use