SID constant tone

[Guest sbaker]

Hello all,

I am building a SID project using the Basic Stamp.  

I have two 6581 SIDs.  When either is connected to the circuit, it produces a constant tone.  

I am able to program the volume of the SID (both behave identically) but no other parameters.  

I cannot control the waveshape, pitch, PWM, etc. .  I do not have the test bit set.  

Has anyone experienced this constant output from the SID before?  

If so, can you provide any insight as to what my coding problem might be?

Any help is greatly appreciated.

thanks --

Steve