On Fri, 2010-07-09 at 07:54 +0200, Johan Nilsson wrote:
>
> - WR (pin 12) of MSM5232 is 5.0V no matter how I send notes. I cannot
> see any pulses since I don't have a scope. If this signal is active
> low, I guess the pulses are to short to affect the DC reading. I
> should meassure this with a scope, but this seems like my small hope
> for non broken MSM5232. In the datasheet for the MSM5232 it looks like
> this signal should be 2.4 - 0.8 V, am I right?
The /WR pin is active low, so it's pulled to around the voltage you say
to tell the chip to look at what's on the data bus. This pulse lasts
for about a microsecond, and you'd need to be quick to even see that
with an oscilloscope. One handy trick is to set the scope to triggered
sweep and use the trigger input to watch things like /WR pulses - if
the /WR pulse happens the scope will sweep.
You ∗have∗ tried programming up a basic patch with both oscillators on
and the filter wide open with no modulation, haven't you?
Gordon MM0YEQ