Author Topic: Zaurus MIDI port?  (Read 2210 times)

raybert

  • Full Member
  • ***
  • Posts: 233
    • View Profile
Zaurus MIDI port?
« on: July 01, 2004, 12:51:41 pm »
Does anyone know of a product that adds a midi port onto a Zaurus or if it's possible to make one using the expansion/serial port on the Zaurus?

I am interested in this mainly for connecting to a guitar processor and backing-up/restoring patch data, etc.  I think the Zaurus would make an excellent tool for an emergency patch restore on the road.

A midi port is just a serial port, I believe, so I think it might be possible to wire one onto the Z's serial port and talk to it using a standard serial driver.

Thanks,

~ray

Fromwithin

  • Jr. Member
  • **
  • Posts: 59
    • View Profile
    • http://fromwithin.com/
Zaurus MIDI port?
« Reply #1 on: July 01, 2004, 01:14:35 pm »
MIDI is standard serial at 31250. The less sophisticated UARTs can't transmit at this frequency (which is why the Amiga MIDI interfaces plugged straight into the serial port, but the PC MIDI interfaces had to work through the GamePort - Amiga serial ports could input/output at any rate).

So there may be someway to use the IR as a serial transfer to some reciever with a MIDI plug on in. Or maybe something else. Is there a Compact Flash serial port available?

tz

  • Full Member
  • ***
  • Posts: 102
    • View Profile
    • http://
Zaurus MIDI port?
« Reply #2 on: July 01, 2004, 05:26:11 pm »
A midi port is an isolated current loop.  I did a $5 midi port ($15 for input too) for the Palm, but the Zaurus might be complicated since it only has limited current and voltage output for its serial out.  Otherwise a resistor to limit current, and the correct polarity to the two MIDI pins would probably work.  At worst you would need some simple electronics (mainly something with a little more power) to change the signal for MIDI.

The Zaurus CAN get close to the MIDI baud rate (base frequency is 921600), BUT there is a bug in the pxa serial driver of the stock rom that prevents setting any but the standard UNIX baud rates (setserial can do so if you patch the kernel).

Then you might just be able to copy raw dumps with "cat", or have a simple midi file player.

raybert

  • Full Member
  • ***
  • Posts: 233
    • View Profile
Zaurus MIDI port?
« Reply #3 on: July 02, 2004, 02:06:56 pm »
Thanks for the info guys.

I'm not an electronics guy but I can handle a solder gun.  If I had reasonably detailed instructions to build this I'm sure that I could do it.  But I'm a little out of my league if I have to figure out the electronics on my own.  Software is another matter; that's no sweat.

I guess I'll look around a little more; someone must have tried this already...

~ray

tz

  • Full Member
  • ***
  • Posts: 102
    • View Profile
    • http://
Zaurus MIDI port?
« Reply #4 on: July 02, 2004, 03:46:17 pm »
This is the Play only version of my palm interface

Code: [Select]
 5 x x 2 x
  |     |     RS232 connector
  |x x x|x
  |     |
  --    <     Diode, Resistor
  /\    <
  |     |
  |  m  |
  m     m     MIDI Connector
m       m