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For AMIGA-Heads Only. Generating An Audio Signal In Text Mode Python. (Python recipe) by Barry Walker
ActiveState Code (http://code.activestate.com/recipes/577971/)

This DEMO is not for the big guns. It is aimed at those who still use a minimum of an ancient classic AMIGA A1200(HD), E-UAE, WinUAE, of which there are still a lot of us about...

No comments about the use of "eval()" as Python Version 1.4.0 does not have "int()" and this is designed to work on all versions of Python available for the above platform. See the code for minimum requirements and much more information.

MANY THANKS to Irmen de Jong for porting early versions of Python to the classic AMIGA to give we lowly users a taste of what was/is to come.

This code will probably make the professionals cough a little, but, boy what fun it is to see how powerful Python can be on an open platform like the AMIGA.

Written in such a way that anyone can understand how it works...

I really don't care how you vote this as it is for those, including professionals, who enjoy messing with AMIGA variants purely for fun and relaxation, and, to......

Enjoy finding simple solutions to often VERY difficult problems... ;o)

Bazza, G0LCU...

Python, 158 lines
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# Ami_Square_Wave.py
#
# DEMO to generate an audio tone from one of the classic AMIGA audio
# channels, in this case a square wave. Almost any waveform is possible
# and the Left Mouse Button is used to STOP this DEMO.
#
# MINIMUM Requirements Are:-
# 68EC020 CPU and 2MB RAM total, example, a standard A1200(HD),
# WinUAE and E-UAE. Standard AMIGA OS3.0x install or better.
# Full Python 1.4.0, minimum, installed, can be found on AMINET.
# (Python 1.5.2 to 2.0.x are also available on AMINET.)
# (Now Python 2.4.6 is available for advanced 68K machines.)
#
# To install just download the file and drag this file into an Assign(ed)
# PYTHON: volume...
# From an AMIGA A1200(HD), E-UAE or WinUAE Python 1.4.0 prompt:-
#
# >>> execfile("PYTHON:Ami_Square_Wave.py")
#
# And away you go...
# ==========================================================================
# The DEMO assembly code that will be compiled and converted.
# Call the code beep.asm...
# From a CLI and using the a68k and blink from AMINET:-
#
# Prompt> a68k beep.asm<RETURN/ENTER>
# Some reports here...
# Prompt> blink beep.o<RETURN/ENTER>
# Some reports here...
#
# This code is TOTALLY, even address, position independent.
# ==========================================================================
# start:
#					;"beep.asm" test code...
#	movem.l	d0-d7/a0-a6,-(sp)	;Save all registers just in case.
#	movea.l	$4,a6			;Set ~execbase~.
#	moveq	#16,d0			;Length of square wave data.
#	moveq	#2,d1			;Set to chip ram.
#	jsr	-198(a6)		;Allocate memory for the task.
#	beq.s	getout			;On error, Quit.
#	move.l	d0,a0			;Set address in chip ram.
#	move.l	#$3f3f3f3f,(a0)		;Set first four bytes of sixteen.
#	addq.l	#4,a0			;Move addres by four.
#	move.l	#$3f3f3f3f,(a0)		;Set next four bytes of sixteen.
#	addq.l	#4,a0			;Move addres by four.
#	move.l	#$80808080,(a0)		;Set next four bytes of sixteen.
#	addq.l	#4,a0			;Move addres by four.
#	move.l	#$80808080,(a0)		;Set last four bytes of sixteen.
#					;This ensures absolute position
#					;independence.
#	lea	$dff000,a5		;Set HW register base.
#	move.w	#$000f,$96(a5)		;Disable audio DMA.
#	move.l	d0,$a0(a5)		;Set address of audio data.
#	move.w	#8,$a4(a5)		;Set length in words.
#	move.w	#64,$a8(a5)		;Set volume to maximum.
#	move.w	#220,$a6(a5)		;Set the period.
#	move.w	#$00ff,$9e(a5)		;Disable any modulation.
#	move.w	#$8201,$96(a5)		;Enable audio DMA, 1 channel only.
# wait:
#	btst	#6,$bfe001		;If LMB pressed then Quit.
#	beq.s	closeme			;Do it.
#	bne.s	wait			;Play the tone until LMB pressed...
# closeme:
#	move.w	#$000f,$96(a5)		;Disable audio DMA.
#	move.l	d0,a0			;Address of the square wave data.
#	moveq	#16,d0			;The data length to recover.
#	jsr	-210(a6)		;Free assigned memory.
# getout:
#	movem.l	(sp)+,d0-d7/a0-a6	;Restore all registers.
#	clr.l	d0			;Set returm code OK.
#	rts
#	nop
#	even
#	end
# ==========================================================================
# The text HEX file to be edited for the Python code:-
#
# Prompt> Type HEX beep > beep.hex<RETURN/ENTER>
#
# Gives a text file "beep.hex" that has the contents:-
# ==========================================================================
# 0000: 000003F3 00000000 00000001 00000000    ...ó............
# 0010: 00000000 00000021 000003E9 00000021    .......!...é...!
# 0020: 48E7FFFE 2C780004 70107202 4EAEFF3A    Hç.þ,x..p.r.N®.:
# 0030: 67682040 20BC3F3F 3F3F5888 20BC3F3F    gZ @ Œ????X. Œ??
# 0040: 3F3F5888 20BC8080 80805888 20BC8080    ??X. Œ....X. Œ..
# 0050: 80804BF9 00DFF000 3B7C000F 00962B40    ..Kù.ßð.;|....+@
# 0060: 00A03B7C 000800A4 3B7C0040 00A83B7C    . ;|...€;|.@.š;|
# 0070: 00DC00A6 3B7C00FF 009E3B7C 82010096    .Ü.Š;|....;|....
# 0080: 08390006 00BFE001 670266F4 3B7C000F    .9...¿à.g.fô;|..
# 0090: 00962040 70104EAE FF2E4CDF 7FFF4280    .. @p.N®..Lß..B.
# 00A0: 4E754E71 000003F2                      NuNq...ò
# ==========================================================================
# With careful manipulation of the Python code you could have control of the
# audio levels, channels, frequency, etc, using this method...
#
# Enjoy finding simple solutions to often very difficult problems...
#
# $VER: Ami_Square_Wave.py_Version_0.00.30_(C)2007-2011_B.Walker_G0LCU.
#
# Original copyright, (C)2007-2011, B.Walker, G0LCU. Now finally issued as Public Domain.

import os

# Manually place the executable code into practical binary string lengths.
one="\x00\x00\x03\xF3\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x21\x00\x00"
two="\x03\xE9\x00\x00\x00\x21\x48\xE7\xFF\xFE\x2C\x78\x00\x04\x70\x10\x72\x02\x4E\xAE\xFF\x3A\x67\x68\x20\x40\x20\xBC"
wave="\x3F\x3F\x3F\x3F\x58\x88\x20\xBC\x3F\x3F\x3F\x3F\x58\x88\x20\xBC\x80\x80\x80\x80\x58\x88\x20\xBC\x80\x80\x80\x80"
three="\x4B\xF9\x00\xDF\xF0\x00\x3B\x7C\x00\x0F\x00\x96\x2B\x40\x00\xA0\x3B\x7C\x00\x08\x00\xA4\x3B\x7C\x00"
volume="\x40"
four="\x00\xA8\x3B\x7C\x00\xDC\x00\xA6\x3B\x7C\x00\xFF\x00\x9E\x3B\x7C\x82\x01\x00\x96\x08\x39\x00\x06\x00\xBF"
five="\xE0\x01\x67\x02\x66\xF4\x3B\x7C\x00\x0F\x00\x96\x20\x40\x70\x10\x4E\xAE\xFF\x2E\x4C\xDF\x7F\xFF\x42\x80"
six="\x4E\x75\x4E\x71\x00\x00\x03\xF2"

# Clear the screen the standard AMIGA way... ;o)
print "\f"

# A simple user screen...
print "1 KHz Square Wave Generator for the classic AMIGA A1200."
print "Using standard text mode Python 1.4.0 to 2.0.1.\n"
print "(C)2007-2011, B.Walker, GOLCU. Issued as Public Domain...\n"

# Show how to change output, (volume), level...
vol=raw_input("Set output level, 0 to 64:- ")

# Don't allow any errors...
if vol=="": vol="64"
if len(vol)>=3: vol="64"
count=0
while count<=(len(vol)-1):
	if vol[count]>=chr(48) and vol[count]<=chr(57): count=count+1
	else: vol="64"
if eval(vol)>=64: vol="64"
if eval(vol)<=0: vol="0"
volume=chr(eval(vol))

# Put them all together as a single binary string.
amiga_exe_file=one+two+wave+three+volume+four+five+six

# Generate a file called SquareWave inside the S: VOLUME and write to the disk.
amigafile=open("S:SquareWave","wb+")
amigafile.write(amiga_exe_file)
amigafile.close()

# Give a short delay to allow system to settle.
os.system("C:Wait 1")

print "\nPress Left Mouse Button to stop...\n"

# Ensure the file SquareWave can be executed.
os.system("C:Protect S:SquareWave rwed")

# Now run it.
os.system("S:SquareWave")
print "This DEMO has now stopped..."

# Ami_Square_Wave.py end...
# Enjoy finding simple solutions to often very difficult problems.

Written in such a way that anyone can understand how it works...

Enjoy finding simple solutions to often VERY difficult problems... ;o)

Bazza, G0LCU...

Tags: amiga, audio, demo, e_uae, sound, winuae

1 comment

Barry Walker (author) 12 years, 4 months ago  # | flag

I never expected anything to come of this upload, however, MANY thanks, from me, to the person who has voted this up on 05-01-2012, you know who you are... :)

Again many thanks...

It seems people are interested in what I do... ;o)

Bazza, G0LCU...