Hi,

Is there a code test I can use to know if BeeSID is present?

I'd like to make a program that plays BeebSID music or normal BBC music depending on if it thinks it's there.

Thanks

PJ

Hi PJ

Yes, you can use Register 27 ($1B). Referring to the text below, I suggest you set Voice 3 to 'Noise' and then read a few samples of R27 - a changing number means BeebSID is present whereas in the absence of the latter, you would get a fixed value. I deliberately picked a base address and I/O map for BeebSID that is only otherwise used by some very scarce hardware so there wouldn't be any risk of confusion.

"Register 27 allows the microprocessor to read the upper 8 output bits of Oscillator 3. The character of the numbers generated is directly related to the waveform selected. If the Sawtooth waveform of Oscillator 3 is selected, this register will present a series of numbers incrementing from 0 to 255 ($FF) at a rate determined by the frequency of Oscillator 3. If the Triangle waveform is selected, the output will increment from 0 up to 255, then decrement down to 0. If the Pulse waveform is selected, the output will jump between 0 and 255. Selecting the Noise waveform will produce a series of random numbers, therefore, this register can be used as a random number generator for games."

Sorry for the slow reply - I got side tracked over the last month.

That works a treat! - I've made a little demo program and once I've finished it I'll post the code.

It seems very useful besides - not only as a quick random number generator but in a way it digitizes the sound stream for you (strange it only does it for channel 3) - you could use it to make a spectrum analyzer!

Thanks!

- PJ