e85rw@efd.lth.se (Ricard Wolf) (12/07/90)
Hi Amiga fans! I friend of mine is wrting som compositional software for his Amiga, to drive synthesizers via MIDI. He has got a small hardware box converting the RS-232 signal levels to the current loop type interface required by MIDI. The problem is, he will be writing the code in BASIC, and he can not set the serial port baud rate to the required 31.25Kbaud requeired by the MIDI protocol. The only possible baud rates seem to be the cannonical 1200,2400,4800 etc. Obviously the serial port can be set to non-standard baud rates, since it has been done in various sequencer programs available for the Amiga. The question is, is it possible to do in a BASIC environment? And in that case, HOW??? Any hints would be appreciated, even short segments of assembler/machine code... Of course BASIC is quite slow compared to MIDI, but he is only interested in driving synthesizers via MIDI out, so even if the serial port is unbufferd on receiving data, it should be possible to write at a reasonable speed. Email would be nice (I don't really feel like wading through tons of Amiga info (I don't actually use one myself (no rotten eggs, please))), but I guess this would have a wide enough appeal to be posted. -- Ricard Wolf +--------------------------+-------------------------------------+ | Ricard Wolf | Lund Institute of Technology | | email: e85rw@efd.lth.se | If you can't buy 'em - build 'em !! | +--------------------------+-------------------------------------+
dtiberio@csserv1.ic.sunysb.edu (David Tiberio) (12/08/90)
Are you using AmigaBASIC? If so, try a compiler such as Blitz or GFA. to open the serial port: open "COM1:19200,n,8,1" as #1 COM1 is the serial port 19200 is the highest baud I have ever used (for my modem) n is "no parity", your choices may differ 8 is 8 data bits (you can use 7 too 1 is 1 stop bit (you can use 0,1,2) then INPUT#1 or PRINT#1 to exchange data. If you want to talk more about BASIC, please contact me. I use HiSoft BASIC for many of my programs.
fillmore@emrcan.BITNET (12/28/90)
Somebody asked a while ago how to set the serial port baud rate to MIDI speed
from an AmigaBasic program. Here is a code fragment from a program I wrote
when I first got my Amiga:
OPEN "com1:9600,n,8,1" as 1
adr1 = &HDFF
adr2 = &H32
adr = adr2 + adr1*4096
POKEW adr,(1000000!/(.2794*31250))
This opens the serial port as usual, but then pokes the hardware to switch to
MIDI speed.
Input can be read as follows:
WHILE LOC(1)<>0
b$ = INPUT$(1,1)
{ process byte b$ }
WEND
Output can be sent by:
PRINT #1,b$;
Keep in mind that the speed will not be very accurate from Basic because
of the slow interpreter speed, garbage collection, etc.
It works well enough to write a MIDI patch librarian, MIDI hex dump, etc.
________________________
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