May 14,1999
	                TestTone EVM56002 DSP Program Description
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	TestTone is a program that was written to provide a tool for testing 
EVM radio interfaces. It is a realtime controllable single/dual tone sine wave 
generator and  port B control program written to run under 'BIOS2' on the 
Motorola EVM56002 DSP evaluation board.  

	TestTone can produce single or dual sine wave signals on either left 
or right channels and provides individual control of the portB output data 
bits. Either tone generator can be directed to the left, right or both channel 
outputs. When both generators are directed to the same port they are 
individually scaled back 6dB and added together to create a two tone output of 
high purity suitable for checking SSB transmitter chain linearity. The 
generator frequencies can be individually set in 1 Hz steps from 1-22000Hz and 
the corresponding outputs can also be individually set in 1 mV steps from 
1-2800 mV p-t-p. The CODEC left/right output electronic attenuators can be 
individually set to any of the  available 0-63, 1.5dB steps to provide the full 
available attenuation range of  0-94.5 dB. TestTone provides a 19.2K Baud 
textual user interface via the SCI port which should be compatible with most 
terminal programs (I have been using the Windows 95 HyperTerminal).   

	Although TestTone is still under development I  have found that it has 
reached the point of being  quite useful for setting up my EVM radio interface 
and for testing the linearity of my transmitter chain. As I think others may 
also find it of use I have decided to upload the TestTone.cld and TestTone.lod 
files onto the TAPR web site for  distribution. As is usual for experimental 
amateur radio programs there are no guarantees implied and use it at your 
~own risk~. Users are advised to take the necessary precautions not to overload 
any equipment driven by the TestTone output signals and are forewarned that the 
outputs may activate any connected equipment. 

	The current  startup initialization default  conditions for TestTone 
are:

		Tone A:
				Frequency:	720 Hz
				Channel:	Left
				Level:		2800 mV  peak-to-peak
				Attenuator:	0 dB
		Tone B:
				Frequency:	1928 Hz
				Channel:	Right
				Level:		2800 mV  peak-to-peak
				Attenuator:	0 dB
		Port B:
				Outputs:		All set to 0 (logic LOW)

	BIOS2 must be loaded first. Then TestTone.cld may be loaded via the 
ONCE port with the Debugger  by selecting LOAD 'TestTone', RESET and RUN.  
Alternately TestTone.lod may be loaded and run via the SCI port with the  
'DL TestTone.lod' command line. When TestTone is up and running it can be 
controlled via the 19.2K Baud SCI port with a terminal program such as 
HyperTerminal. Press 'H' for the command functions help screen.

	I wish to acknowledge Douglas Braun, N1OWU for his assistance with the 
development of TestTone.

	I would like to hear from others who use TestTone. Please send any 
comments or questions you may have to me by email.

73 and Enjoy!
Thomas M. Alldread, VE7TMA
tma@island.net