Talk:MPU-401

q
What is a MIDI interface good for? --Abdull 23:47, 25 August 2006 (UTC)

MIDI is/was the standard control interface used on just about every pice of pro or semi-pro electronic musical instrument hardware built in the mid-to-late 1980s, and the 1990s. It lets you plug in a remote keyboard or sequencer to play the unit's onboard sounds, or use the unit's own keyboard to control external equipment.

Typically, it lets you plug all your electronic equipment into a computer and have the computer record your keyboard actions and play them back. There's also some pretty advanced sequencing software that lets you change the notes and timings, and which instruments they're to be played on, kinda like the musical equivalent of a word-processor.

Most commercial dance and pop music tends to be done on computers and sequencing hardware nowadays. In the early 1980's when MIDI was first launched as a universal interface for synthesisers and keyboards and drum machines, the '401s were probably the first generally-available commercial interfaces that'd let you connect your MIDI devices to a range of computers. If not the first, it was certainly one of the first. The Atari ST was an exception, in that it came with a MIDI interface already built-in (I think one of the Yamaha computers also had onboard MIDI).

After the 401, some soundcards came with an onboard MIDI interface, but since the MIDI connector is wider than a PC PCI panel, they usually had to use breakout boxes. Nowadays, MIDI interfaces tend to be USB devices, and increasingly, instrument manufacturers have started building "virtual" USB MIDI interfaces directly into their equipment, so that you can plug your keyboard or soundbox straight into your PC using just a standard USB cable. ErkDemon (talk) 14:42, 24 April 2010 (UTC)

MPU-401 chip?
I was pretty sure that the UART chip used in the MPU-401 interfaces was also supposed to be called the MPU-401, and that this was a specific chip that the interfaces and the standard were named after. But I haven't added this to the article because I couldn't find a supporting reference. Not that I've ever actually peered at the chip on an "original" MPU401 card to check, it's just something I'd always kinda assumed. Does anyone know for sure?

If you zoom in on the article's picture of an opened MPU-401 interface, you can just about make out that the "big" chip carries the Roland name and logo, but unfortunately the image resolution isn't high enough to let you make out the next line with the chips' designation code. :( ErkDemon (talk) 14:42, 24 April 2010 (UTC)
 * There's no chip named MPU-401. The large chip you are referring to in the picture is a Motorola 6800-compatible 6801 microcontroller (HD6801V0B55) with integrated mask ROM. Earlier PCB revisions would use a 6801 without integrated mask ROM, putting an external mask ROM in the white-outlined area.
 * Even in later years, Roland never produced a single-chip MPU-401. The closest they ever came to it was the 2G1/2J1, which is a tiny piggy-back PCB carrying three epoxy blobs, seen on the SCC-1 and LAPC-N, not the MPU-401/AT. NewRisingSun (talk) 19:00, 25 April 2010 (UTC)