| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 2295.1 | This is a DIN cable, can you say that? | TOCATA::PICKETT | David - Beware of the dogma. | Thu Mar 22 1990 15:29 | 6 |
| Dunno about the address, but you may wish to consult the book 'MIDI for
Musicians' by Craig Anderton. It has the MIDI spec as an appendix. The
spec hasn't changed a lot since rev 1.0. The rest of the book is all
but worthless.
dp
|
| 2295.2 | part 2... | TOCATA::PICKETT | David - Beware of the dogma. | Thu Mar 22 1990 15:43 | 12 |
| Oh yeah, and part 2....
According to an ad in EM 3/90 pg56
PC MIDI Card $119 from Music Quest 214-881-7408
I cannot vouch for this, but I remembered the ad, and it looks like
what you need. Also, you can consult Byte mag from a few years back,
they had a two part article on building your own IBMPC MIDI card.
Fairly cheap, as I recall.
dp
|
| 2295.3 | Do not pay list | STAR::NORCOTT | Wakarimasu ka? | Thu Mar 22 1990 21:36 | 8 |
| RE:
PC MIDI Card $119 from Music Quest 214-881-7408
Get the card, I have one and it works great. Do not pay full price,
get it mail order from Soundware (800-333-4554) for $99.
Bill Norcott
|
| 2295.4 | what are you gonna write, anyway? | SWAV1::STEWART | As a matter of fact, it's all dark | Fri Mar 23 1990 15:01 | 18 |
| > 2 Where do I get the hardware to plug into the PC - like
> the Card with the Midi plugs/sockets? Or do I have to
> make 'em myself and if so HOWWWWWWWWW?
Another alternative for this might be from MusicQuest (??)...I
forget the actual name of the outfit. I bought my MPU-401 clone
board (the Roland MPU-401 is the original and default standard
for PC clone MIDI interfaces) from these guys and got a real
stupid sequencer as part of the deal. The only reason I mention
these guys at all is that they also offer a C programmers toolkit
for writing your own stuff. Might give you a head start on your
project. Check the back pages of EM. If you can't find them I
could be persuaded to sell you my virgin copies...I've never had
the time/inclination to look at the stuff.
P.S. the board I got from these guys doesn't do tape sync,
either...fine print in the back of one of the manuals
|
| 2295.5 | MIDI current-loop spec, please? | CTHULU::YERAZUNIS | Iconoclasm as a way of life... | Tue Oct 23 1990 19:44 | 17 |
|
A quick question to anyone who happens to have a MIDI 1.0 spec at
their fingertips:
I) MIDI inputs are defined as a current-loop; typically an LED input to an
optoisolator. What is the expected minimum impedance (i.e. is there an
inline resistor?)
II) MIDI outputs are defined as current loop drivers; what's the
required minimum/maximum voltage and min/max current? Or do they
just give an op-amp part and an in-the-line resistor?
Reason I ask: I wanna build a MIDI "Star Coupler" and I wanna build
it cheap. So what if it loses a few notes once in a while... :-)
-Bill
|
| 2295.6 | This help? | WEFXEM::COTE | Light, sweet, crude... | Tue Oct 23 1990 21:11 | 27 |
|
> A quick question to anyone who happens to have a MIDI 1.0 spec at
> their fingertips:
Just happen to have the specs right here...
> I) MIDI inputs are defined as a current-loop; typically an LED input to an
> optoisolator. What is the expected minimum impedance (i.e. is there an
> inline resistor?)
There's a 220ohm resister between pin 4 of the MIDI in and PIN 1 of the
opto. (Typically a Sharp PC-900)
< II) MIDI outputs are defined as current loop drivers; what's the
required minimum/maximum voltage and min/max current? Or do they
just give an op-amp part and an in-the-line resistor?
The spec defines the circuit as 5mA current loop, optos should require
less than 5mA to turn on (logical 0). Rise and fall times <2usec.
+5V running thru a 220ohm resister. No min/max voltage given.
Edd
Reason I ask: I wanna build a MIDI "Star Coupler" and I wanna build
it cheap. So what if it loses a few notes once in a while... :-)
-Bill
|
| 2295.7 | The definitive answer. | EICMFG::BURKE | Jim Burke, @UFC | Wed Oct 24 1990 20:01 | 9 |
| ...hardware expert speaking (short burnt fingers, note)...
The diagram I have has a +5v going into (coming out of) the MIDI OUT
port. And there's a 200 Ohm doobrie inbetween.
Any more questions Bill: don't be afraid to ask (!)
Jim
|
| 2295.8 | So far, so good. | CTHULU::YERAZUNIS | May the moon light your way, till the wind sets you free. | Thu Oct 25 1990 18:58 | 7 |
| So, electronically speaking, the MIDI output port ought to look like
a "perfect" 5 volt source with a 220 ohm resistor in series, and a
MIDI input port ought to look like a 220 ohm resistor?
Or do I have one too many 220 ohm resistors?
-Bill
|
| 2295.9 | | WEFXEM::COTE | Light, sweet, crude... | Thu Oct 25 1990 19:24 | 20 |
| o +5V
midi in |------- |
2| |6 | 270ohm
pin 5----------------------------o-------| |-----+/\/\/\
V IN914 |PC900 | |
+ (D1) | |-----+------+--->UART
pin4-------------------/\/\/\/---o-------| | |
220ohm 1|---+--- |
|5 V to thru
-----
---
-
midi out
220ohm
+5V---------------/\/\/\/------Pin4
|
||------------------pin2 (to shield)
|
from UART----------/\/\/\/-----pin5
220ohm
|
| 2295.10 | And what does "idle" sound like? | CTHULU::YERAZUNIS | You can't fall off the floor. | Fri Oct 26 1990 11:48 | 7 |
| OK, thanks; it seems that there's a total of 660 ohms in the line- one
on each leg of the transmitter, and one in the reciever. No problem!
Now, is the "idle" condition with no current flowing, or with current
flowing? (a 1 or a 0 coming out of the UART) ?
-Bill
|