Silent

I have managed to get the (almost) stable tones. In some special cases I am still getting 2 options, but looks like proper reset sequence (when cycles are not counted) does the job. My current sequence is: SKCTL = 0 AUDF0 = 1 AUDF1 = 1 STIMER = 1 AUDF0 = xx AUDF1 = yy SKCTL = 3 I have also noticed that setting the register (CS0=L, CS1=H during 1 clock cycle, both edges) does not take an effect when the value was not changed. For example when using unstable tones - tone changes after first write and another write does not change it. Writing something different then the previous value takes an effect and the tone is "random" (if unstable). However, the older chip revision which comes from 5200 board (CO12294-03) acts differently. Every write takes an effect and the Synthpopalooza's table for distortion 12b ("smooth", divisible by 3) is not stable (at least in my case; same setup, only the chip was replaced). It was stable on CO12249B-01 (from 65XE). Do you know what are the differences between chip revisions?

Thank for your reply! I still have a problem with synchronization. When (freq+1) is divisible by 3 or 5 I am getting different timbers with the same settings. As phaeron wrote, it depends on timing (when the AUDCn/AUDFn was set). How to get in sync so I can get the same timber every time? Is there a "magic sequence" to reset all counters? How do you control it in your program?

Hi. I am building a synthesizer based on a microcontroller and multiple pokey chips. I have noticed this timing-related behaviour - the tone depends on the moment of change. When using distortion 12 (AUDC1 = 0xCF) I am getting "tone or no tone" with AUDF1 = 64. Why is it so? ((64+1) * 28) mod 15 is 5, so if the pattern is 00011 10110 01010, there are 5 possible sequences - 010, 001, 010, 111, 100. In case of sequence 111 there is no sound. Am I correct? Is there a way to get in sync with (or reset) the timer driving shift register? Btw. why "distortion 10" (AUDCn = 0xA*) is named "distortion"? Isn't it a clear tone?