data with low latency a 16MHz bus mixer is implemented in the
workstation. To mix from outside the workstation a 32 input
/ output MIDI board was created performing with 200 MBit of
bandwidth and transports data with only low latency.
mixer is the same wich already was used in the
S/PDIF Mix Matrix.
32 x 32 channel - mixer / router:
The FPGA can easily handle 32x32
virtual MIDI channels and route them from and to any source
and destination nearly no latency. To handle 2x2 times the
mixer's capabilities, 16 sub mixers are used running on 16
MHz each. Thus 8x8 x n paths operate at 31,250bps.
classic MIDI channels are grouped together and mixed into
one of 4 S/PDIF channels by using a 32 x 4 word input buffer
and four switch lanes at 32 MHz raw bandwidth.
in the former switch version, all channels can be routed to
all outputs performing like an Ethernet-router. Therefore
all inputs are registered with a 2-word input buffer and
eventually switch to a 8 word output buffer. So 8 MIDI-input
channels can drive the same output at the same point of time
without overloading it. Currently there is no commercial
studio device which can do this.
32 channel - IO - PCB:
A new Cyclone II FPGA from Altera is used using Quartus
The Design has been done with
Development has been done with a
evaluation board system:
real time signal test
A test of
the signal including latency measurement is performed by a
usb-based logic analyser from Intronix. It is able to
measure signal delays with a precision downto 4ns
about the former version:
MIDI switch 32x32