MIDI support?

alraz

New Member
Sep 14, 2019
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Was wondering if there are any plans to support MIDI output (or input!) either directly or through add ons.
 
May 22, 2019
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At the moment, there don’t appear to be plans by David or the team to build an official MIDI interface.

However, MIDI certainly is feasible through the expansion ports. It would require a custom PCB, however, and it would obviously also require new software for the system.
 

christo

New Member
Sep 16, 2019
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If I understand correctly, MIDI is elecrically equivalent to RS232 - I'm a big fan of supporting that (and MIDI also). If there is a header or some other RS232 port, then a MIDI interface cable is all you'd need.
 
May 22, 2019
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If I understand correctly, MIDI is elecrically equivalent to RS232 - I'm a big fan of supporting that (and MIDI also). If there is a header or some other RS232 port, then a MIDI interface cable is all you'd need.
No, MIDI is a balanced signal, where RS-232 is unablanced. MIDI also runs at (IIRC) 32kbaud, which is not a common speed for RS-232 interfaces.

The best choice really is to use a MIDI transceiver, although it can be faked with the right balancing circuit.

 

Ohjurot

New Member
Sep 13, 2019
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München (Germany)
I‘m currently working on a midi expansion card. I just startet building basic midi circuits and tinkering with the midi protocol. I will soon start a new thread here to get some detailed information about the expansion ports. I don’t know how far this goes but if there is enough demand i may sell the card. But for now I have to work on an other project. I will keep you updated!
 

easyprototype

New Member
Sep 21, 2019
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Canada
Honestly I think the Commander X16 should feature more IO ports as standard. Namely the MIDI ports we are discussing here and at least a serial port. a MIDI port with super low latency is one of the features that made the Atari ST survive to this day. MIDI ports with the 2 onboard sound chips would make the X16 a must for chiptune/synth lovers and composers. BASIC commands for the MIDI port could be added too, opening more options :)

A I2C port adressable directly from the address/data bus (ex: PCF8584) would be amazing for interfacing all those nifty breakout boards available to electronics hobbyists, but such chips a quite specialized. Okay, the I2C should be an expansion card...
 
May 22, 2019
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Honestly I think the Commander X16 should feature more IO ports as standard. Namely the MIDI ports we are discussing here and at least a serial port. a MIDI port with super low latency is one of the features that made the Atari ST survive to this day. MIDI ports with the 2 onboard sound chips would make the X16 a must for chiptune/synth lovers and composers. BASIC commands for the MIDI port could be added too, opening more options :)

A I2C port adressable directly from the address/data bus (ex: PCF8584) would be amazing for interfacing all those nifty breakout boards available to electronics hobbyists, but such chips a quite specialized. Okay, the I2C should be an expansion card...
GPIO is definitely a worthwhile thing on modern microcontroller based systems, and having SPI, I2C, and RS-232 I/O would be super useful. On the other hand, all of these things require additional hardware to support, and the team has decided to focus first on making the core computer work as well as possible, leaving expansions for other people to develop.

There are several ways to interface to external hardware, and with the 4 expansion ports, it should be possible to create an interface for any conceivable communications protocol. The best thing to do is going to be to focus on building expansion cards for serial and network communications. Of course, this can't really happen until we have a final design for the expansion ports, so this kind of thing is still a ways off.

The best thing to do for now is look at the memory map and the design of the existing system. I ask on FB about a pinout for the existing expansion connectors, but David said in his video that this might be changed to a different connector format. Regardless, knowing what bus lines are available on the expansion ports will help.

** update: reading the Programmer's Reference Manual, I don't think they're anywhere near ready to finalize an expansion bus connector format. In fact, they are still making architectural changes, as they recently moved the SD card interface and the system clock generator to VERA.
 
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