The program writes directly to the hardware of the CPC.
You can use the port with the adress address &EFxx.
Because the CPC has only a 7bit printer port (we need 8bit for the Digiblaster) we use the STROBE signal, which is inverted by the hardware, so you have to invert your sound value.
Now we want to output the value &C5:
<pre> LD a,&C5 ;A=&C5 LD B,&EF ;load the port adress address XOR &80 ;invert the 7th bit OUT (C),A ;out to the printer port LD a,&C5 ;A=&C5 LD B,&EF ;load the port adress XOR &80 ;invert the 7th bit OUT (C),A ;out to the printer port </pre>
The accu is the register A.
The different resistor values are:
D7 STB D6 D5 D4 D3 D2 D1 D0
v1 1K 2K2 4K7 10K 22K 39K 82K 150K
v2 1K 2K 4K 8K 16K 32K 64K 128K
Where v1 uses standard E12-series values. Whilst v2 uses less common values like 2K (which you may not have at home), and even totally non-standard values like 4K (which aren't manufactured, and need to be produced by using two 2K resistors).
== Notes ==
* '''Caution''' Both schematics connect GND to Pin9, which works on the CPC's (unmodified) [[Connector:Printer_port|7bit printer port]], but not on (upgraded) [[8bit Printer Ports]], so better connect GND elsewhere (eg. Pin19).
* As said above, Strobe is inverted by the CPC's printer port hardware. And, when using '''unsigned''' samples, it must be actually inverted by software. However, with '''signed''' samples, that hardware feature is just perfect, and no inversion is needed.
== Diagram (Digiblaster v1) (Andreas Stroiczek) ==
[[Image:Digiblaster_diagram_v1.png]]
== Diagram (Digiblaster v2) (Joshua/Exodus) ==
[[Image:digiblaster diagram.jpg]]
''Converted 1996/1998 by [[Octoate]]'''
[[Category:Digiblaster]][[Category:DIY]][[Category:Programming]] [[Category:Printers and printer ports]] [[Category:Music and sound]]