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MIDI to RS232 interface with LTC interface?


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Hi everybody, I was thinking about make a MIDI-to-RS232 interface, using the midimerger, my idea is to have 1 in and 1 out at 31,250 baud (MIDI), and at the same time using the LTC module to send/receive data thru the PC's serial port. But seems that only a MIDI IN I can obtain using these both projects. Anyone try to do this before? Have some idea?.

Thanks for your time.

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  • 1 year later...

There was a MIDI <-> RS-232 converter in issue 04/2001 of Elektor magazine.

It gets MIDI bytes at 31250 b/s and forwards them to serial port at 38400 b/s.

The other way it stores serial port data coming at 38400 in a FIFO and forwards ASAP to MIDI at 31250.

The Windows driver is from Yamaha at http://www.global.yamaha.com/download/cbx_midi/index.html.

Instead of software UART like in MidiMerge with PIC, it used a DS80C320 microcontroller (8051 family) that has a second hardware UART and a 128 bytes FIFO, running at 24 MHz for MIDI baud rate and using 1.8432MHz crystal oscillator for PC baud rate. That was an old design with external RAM and EPROM. Most of today's microcontrollers have on-chip Flash and SRAM.

I redesigned it with a DS89C430 with 1Kbyte FIFO, running at 32 MHz, and using second osc at 3.6864MHz. Thanks Maxim/Dallas for the free sample. It has a builtin bootloader and can be programmed onboard with their MTK utility and HEX file from assembler.

For PIC haters like me (I learned 8052 quite fast but vomited after reading PIC datasheets and mnemonics :P), the DS89C430 is fast enough to implement some MIDI filters or generators, using port I/O (23 free port pins) or memory-mapped up to 63K address space.

If somebody is interested in such alternative MB hacks or just the basic MIDI<->RS232 baud rate converter, I can share modified schematic and source code.

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Great Stuff!

As I recall, the Yamaha CBX Driver also supports multiple MIDI Outs, up to at least 3 (maybe more)

A few extra bytes in the MIDI stream could switch between the outputs. This does NOT give you 3X the bandwidth, but you do get 3X the addressing capability.

I was using this feature on my MU90R for a long while when I had no MIDI interface available.

LyleHaze

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If somebody is interested in such alternative MB hacks or just the basic MIDI<->RS232 baud rate converter, I can share modified schematic and source code.

Wow, that's impressive silicium! I can't use it myself but it's sure got my curiosity going anyway :D

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