Which MS-20 do you have? If it's an original MS-20 from the 70's, you can't do it. If you have one of the reissues, then, yes you can.
The BSP inputs are MIDI and clock (analogue clock or DinSync24). Out of those two input formats, only MIDI carries note messages. As the original MS-20 was before the MIDI era, the BSP would need a CV input (Hz/v) for the MS-20 to send it notes.
If you have one of the reissues, then you can link the synth to the sequencer via the USB MIDI out on the synth, though you may as well just use a computer in this situation as the reissues don't have MIDI out on DIN5 sockets. If you have the spare cash, you can get a MIDI USB host box (such as the ones made by Kenton and Keith McMillan Instruments) to convert the USB MIDI to MIDI DIN and send that to your BSP. That would remove the computer from the chain.
