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Old 30 June 2014, 14:50   #12
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Originally Posted by Ami_GFX View Post
Midi is a hardware and software specification. It is not very fast by modern standards and even back in the day it wasn't considered that fast. It works fine with with one device on one cable controlling another but when multiple devices on different channels are controlled by one port, the timing gets muddy to the point that timing errors are easily perceived by the human ear. That is why there were multiport adapters for all the big sequencing platforms for the ST, Mac, Amiga and PC. Each synth in a complicated setup could have its own Midi port.
There is no multiport MIDI per se as in ST or Amiga you have only one serial port - to do multiport you need some smart buffer and sufficiently faster main serial port co combine data from multi port solution - AFAIK there is no such HW for ST thus there is no real multiport MIDI on ST.
Of course smart buffering can be done on some uC with proper (embedded software) then you can have multi I/O MIDI but still this will be kind of hack - pure math nothing else.

Originally Posted by Ami_GFX View Post
On the hardware level, Midi is a serial port with an opto isolator and a fixed data rate to be exact. The serial to Midi adapters added the opto isolator to the Amiga serial port. The Midi specification has input and output and thru ports and most devices have at least input and output ports.

The ST had Midi interupt service routines in ROM for the MIDI ports which were pretty fast and a programer could substitute these for custom routines by simply switching an interupt vector. There were MIDI functions in the ST's bios as well. This was the foundation upon which all ST midi software was built.
Yep - ST use MC6850 for this but beside slightly offloaded data processing (as Amiga use more RAW stream than data) there is no significant differences in Amiga (and as Copper can write to UART perhaps latency can be reduced slightly on Amiga).
btw 6850 seem to be informal standard for MIDI even on PC world - i saw MIDI cards on ISA where 6850 was used for this.

Originally Posted by Ami_GFX View Post
The Mono Monitor was indeed a plus and made doing complicated sequencing easier on the ST but I think it was a combination of factors that gave the ST the lead in Midi. It was simply having the right hardware and software at the right price at the right time. For the Amiga, the same thing happened with the Video Toaster and even before that with earlier video and animation software and hardware that led to the Toaster.
IMHO SM124 with Atari ST was best price/value for MIDI - Amiga can beat this only when flickerfixer will be standard (or from ECS/AGA by using no flicker mode mode), also SM124 was relatively small and light weighted thus additional bonus for musicians...

Atari ST was simply a good sequencer where Amiga was under some limitations also sampler thus why Atari was better (sometimes less is better).

btw - one of first MIDI equipped computers was Yamaha CX5M - where CPU was Z80A (MSX standard) - this shows that MIDI doesn't have particular high demand on processing power - even 8 bit CPU was capable to act and control MIDI.
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