The ParallelSID power supply seen from below.
Schematics of the power supply
OK, i know that a 15 V transformer would have been more than satisfactory, but i can get those 19 V ones here at an electronics store for 1.50 DM (appox. 0.75 US$), so i think that justifies using it. As you can see, nothing spacial here. Maybe the bypassing caps could have been smaller (especially when taken in account that there is a maximum current of 10 mA), but for audio i do not want any hum.
Schematics of the audio/logic board
Not very much more to add here. Port C of the 8255 is unused, also the audio input of the SID (pin 25) is not connected. The 8255 does not need any clock information, that makes it an ideal candidate for multiplying parallel port lines; it is also very robust and inexpensive.
Much people do have only access to the later made Commodore 64C (in germany konwn als C64-II), which uses the 6582 Sound chip. Besides of some people saying that itґs sonic qualities are not the same as of the 6581, it needs a power supply of 9 Volts instead of 12 Volts. (You can simply replace the 7812 regulator IC in the power supply by an 7809 to do this.)
Exact wiring diagram DB25 to 8255:
| Parallel Port DB25 | 8255A | ||
| Pin (bit) | Name | Pin | Name |
| 2 | Data 0 | 34 | Data 0 |
| 3 | Data 1 | 33 | Data 1 |
| 4 | Data 2 | 32 | Data 2 |
| 5 | Data 3 | 31 | Data 3 |
| 6 | Data 4 | 30 | Data 4 |
| 7 | Data 5 | 29 | Data 5 |
| 8 | Data 6 | 28 | Data 6 |
| 9 | Data 7 | 27 | Data 7 |
| 1 (0) | -Strobe | 9 | Address 0 |
| 14 (1) | -AF | 8 | Address 1 |
| 17 (3) | (???) | 35 | Reset |
| 16 (2) | Init | 36 | -Write |
| 18...25 | GND | - | GND |
| P/S | (+5V) | 5 | -Read |
| P/S | (0V) | 6 | -CS |
Exact wiring diagram 8255 to SID:
| 8255A | SID 6581 | ||
| Pin (bit) | Name | Pin | Name |
| 18 | Port B 0 | 9 | Address 0 |
| 19 | Port B 1 | 10 | Address 1 |
| 20 | Port B 2 | 11 | Address 2 |
| 21 | Port B 3 | 12 | Address 3 |
| 22 | Port B 4 | 13 | Address 4 |
| 23 | Port B 5 | 8 | -CS |
| 24 | Port B 6 | 7 | R/-W |
| 25 | Port B 7 | 5 | -Reset |
| 4 | Port A 0 | 15 | Data 0 |
| 3 | Port A 1 | 16 | Data 1 |
| 2 | Port A 2 | 17 | Data 2 |
| 1 | Port A 3 | 18 | Data 3 |
| 40 | Port A 4 | 19 | Data 4 |
| 39 | Port A 5 | 20 | Data 5 |
| 38 | Port A 6 | 21 | Data 6 |
| 37 | Port A 7 | 22 | Data 7 |
Schematics
of the audio/logic board (Click on the image to get the 300 DPI printable
version (ca. 60 K))