Midi Merging with several inputs, bidirectionnal

[silicium]

Are the state machines for midi merge described somewhere at midi message level ? I would like a better midi merge box with COM I/O to PC (to have two merged MIDI inputs and one output on any PC, using compatible baud rate of 38400, with at least one COM port but without using USB). I plan to use a double UART like SCC2692 and external RAM or asynchronous FIFO chips, at least twice larger than PIC18 internal RAM, and have not chosen the target microcontroller yet (PIC or 8052). How are working the ringbuffers of MM ? I don't need to filter content, not interested in the MidiRouter design.

[stryd_one]

You don't have to filter data to use the midibox router. It does just what you've described, but if you want to reinvent the wheel....All the info about midi is online. Try google, and midi.org.

[seppoman]

And why do you need large external RAM and UARTs/FIFOs for that task? even with large buffers for each of your (few) Midi ports, you won't ever get close to being limited by RAM size.

S

[ilmenator]

Buffer size can be an issue with multiple SysEx strings at the (multiple) inputs. Yet, this is rather an academic problem...

Best regards, ilmenator

[madox]

Buffer size can be an issue with multiple SysEx strings at the (multiple) inputs. Yet, this is rather an academic problem...

Best regards, ilmenator

Yes, have to agree. Buffer size is not likely to be a real problem, but I guess it depends what one plans to use the interface for. Personally, whenever I am going to send much sysex data (bulk dump, firmware update, etc), I will make sure that there is no other midi trafic at that time.

I am currently planning to make a midi merger with a few more I/Os, to go with the USB midi chips currently being ordered in the bulk orders forum. I will most likely use one PIC24Fxxx for each merger unit. These PICs have 4 hardware UARTs, and I will probably use one or two software driven UARTs as well. I don't imagine RAM limitations will be an issue, as midi is a rather low data rate, and being real time, one should not be buffering a great deal of data anyway.

If/when I finish my design, I will make it available online. However, I'm pretty sure that existing solutions would be able to meet your requirements, unless you are planning a different kind of usage from what I am expecting to be the way that most people use midi.