Posted By
IstvanV
on 2008-07-02
18:21:17
|  Re: TED-Oscillators
One thing that is not emulated accurately yet is the exact way the noise generator is reset by the MSB of $FF11. If the bit is set for a "long" time, then the noise pattern just restarts from the beginning (starting with 01100100001...) as expected, but setting it for a very short time (only a few cycles) only seems to reset it partly on the real machine, as if e.g. the shift register is not immediately set to $FF, but rather the 1 bits are shifted in one at a time at some rate.
For the square oscillators, I found that setting the "test" bit immediately resets the state to 1, but the counter is only reloaded on the next 221.7kHz cycle; this seems to emulate the output of the real machine correctly.
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