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1993-10-07
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*** PLAYLPT.EXE *** 01-08-93 Audio Sample Player Unit Test by John C. Howard
Plays .VOC, .WAV and .RAW and .SAM files through the LPT printer port.
Syntax example...
PLAYLPT {sample filename} [rate(default 11000)] [port address(default 378h)]
This program doesn't use DMA transfers for data output as most others.
Instead it hooks the timer and increases its interrupt rate according
to the sample rate while outputting bytes to the lpt port on each interrupt.
This isn't the most stable way to do it, but it works fine for
samples up to about 16000 Hz on a 33MHz processor.
This is how I torture myself when I'm not at work.
Any questions or input?
Call me at 609-596-0048 in Marlton.
If you get an answering machine, leave a message,
I do return calls.
******************************************************************************
Build your own Digital to Analog Converter..............
... taken from mp.exe and modrec.exe doc files.
Two very good mod programs!
Printer Port:
signal pin 20k 20k
D0 2 >───░░░─┬─░░░───────────────0v
20k ░ 10k
D1 3 >───░░░─┤
20k ░ 10k
D2 4 >───░░░─┤
20k ░ 10k
D3 5 >───░░░─┤
20k ░ 10k
D4 6 >───░░░─┤
20k ░ 10k
D5 7 >───░░░─┤
20k ░ 10k
D6 8 >───░░░─┤
20k ░ 10k
D7 9 >───░░░─┤
20k ░ 10k + 1uF
├────────┬───────┤├───> TO AMPLIFIER
│ ░ 1k
│ │
░ 10k === .1uF
│ │
GND 20 >───────┼────────┴─────────────>
0v
This is slightly modified from its source. I added
a 1kHz - 3bB per octave low pass filter.
Make sure all 0v (Gnd) are connected together.
Use only 1% resistors. 15k ohm resistors in place of the
20k ohm 1% resistors sound retched, and 22k ohm aren't
good either.
I packaged my own in a serial port gender changer type adapter
connector (perfect size). the finished product cost under $5.00
and took about an hour to assemble.
... taken from Whacker Tracker's doc file.
Parallel Port
pin no
2───────────── 2.8 MΩ ────────────┐
│
3───────────── 1.4 MΩ ────────────┤
│
4───────────── 0.7 MΩ ────────────┤
│
5───────────── 352 KΩ ────────────┤ ┌────────────┐
│ │ │
6───────────── 176 KΩ ────────────┤ │ Amplifier │
│ │ or any │
7───────────── 88 KΩ ─────────────┤ │ kind of │
│ │ Hi-Fi- │
8───────────── 44 KΩ ─────────────┤ │ system │
│ │ │
9───────────── 22 KΩ ─────────────┴───────┤20uF├────┤ │
│ │
18───────────────────────────────────────────────────┤ │
(gnd) └────────────┘
******************************************************************************