SD MIDI II plus Payer V0.2
Dear Friends and customers,
It's up to what I've been working on recently.
The biggest change in this version is the player used as far as the hardware supports it.
It support a progressive bar (level meta).
It is very tight to support this in the 1Mhz APPLE II.
It was made using even the hardware timer and interrupt supported by the SD MIDI II card.
It is quite difficult to support it.
After a lot of trial and error, I finally decided to use a timer interrupt for simultaneous processing.
For reference, these progressive bars are the 16 channels of MIDI, from 0 to 15 from the top.
It seems that it is too difficult to handle this with interrupts in Apple2.
It's so hard that I don't want to bother you anymore.
It works fine with or without an accelerator card but, If you use an accelerator card, the CPU load is reduced, so the tempo of the sound can come out a little more naturally. This is because the load on the interrupt side is large.
Since you have to use PRODOS, you can't completely push the IRQ routine away, so this is the best what I can do.
If I increase the speed of the progressive bar quickly, the CPU load increases, so this is the last choice.
it is a thankful result with APPLE II.
Now I have waht I wanted.
Please enjoy listening.
** Some more information **
- MIDI file format 0 is supported. Other formats can be played smoothly by converting them to MIDI 0.
- There is no MIDI file size limit. However, if the file is large, a slight delay may occur. This is sometimes canceled by the internal timer when a delay occurs, but in some cases, it cannot be canceled and may exist as a sound delay.
It isn't a freeware sorry bout it but, I will provide SD MIDI][+ customers for free.
Thank you
Ian Kim