19-12-2020, 08:39 AM
(This post was last modified: 23-12-2020, 07:53 AM by someone.
Edit Reason: Changed Subject Title
)
A microbee that is equipped with a BEETHOVEN (AY-3-8910) or onboard SN76489 Programmable Sound Generators have limited capabilities.
To make full use of these devices additional hardware is required to extract improved results.
This doesn't mean the microbee can't make some great noises. It can but can't do anything else whilst doing so.
High resolution Hardware timers such as the Z80 CTC are vital for producing sampled or complex sounds whilst multi tasking.
Unfortunately the microbee does not have one installed as standard.
To make complex sounds beyond just square wave soundtracks and noise, substantial CPU intervention is required consuming valuable CPU capability away from more important tasks such as game play. This makes it difficult (if not impossible in many cases) to play back complex sounds whilst having good application performance.
A method to reduce CPU intervention is the addition of hardware audio filtering.
This method can comprise of an additional output port that can connect selected capacitor values to the audio channels.
This only provides limited alteration to the PSG sounds.
Amstrad when part way to improve their sound generation of the CPC Plus models by implementing a DMA engine to feed data to its PSG using its gate array.
It works well allowing good application performance with good sounds.
To truly get the most out of these PSG devices, it is best to incorporate the abovementioned features and include a dedicated slave CPU and memory for audio processing.
This technique is used by some early to mid 1980's arcade and gaming machines such as Frogger and Galaga.
To make full use of these devices additional hardware is required to extract improved results.
This doesn't mean the microbee can't make some great noises. It can but can't do anything else whilst doing so.
High resolution Hardware timers such as the Z80 CTC are vital for producing sampled or complex sounds whilst multi tasking.
Unfortunately the microbee does not have one installed as standard.
To make complex sounds beyond just square wave soundtracks and noise, substantial CPU intervention is required consuming valuable CPU capability away from more important tasks such as game play. This makes it difficult (if not impossible in many cases) to play back complex sounds whilst having good application performance.
A method to reduce CPU intervention is the addition of hardware audio filtering.
This method can comprise of an additional output port that can connect selected capacitor values to the audio channels.
This only provides limited alteration to the PSG sounds.
Amstrad when part way to improve their sound generation of the CPC Plus models by implementing a DMA engine to feed data to its PSG using its gate array.
It works well allowing good application performance with good sounds.
To truly get the most out of these PSG devices, it is best to incorporate the abovementioned features and include a dedicated slave CPU and memory for audio processing.
This technique is used by some early to mid 1980's arcade and gaming machines such as Frogger and Galaga.