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Location: Sweden

Paula (MOS8364) tracker player idea

Thu Jan 10, 2013 11:40 pm

Recently I've been tinkering with a SID chip (MOS6581) and an atmega328 in order to be able to play chiptunes the way it was ment!
I'm influenced by the sidaster shield but is building mine "free hand" with two 74HC595N shift registers and one 6N138 octocoupler for a midi interface.

The thing works fine but as I was soldering away I came to think of an even greater project - Paula tracker module!

I have a spare Paula (MOS8364) pulled from an old Amiga 500 and I would love to wire it up to a Raspberry Pi in order to correctly play back mods and make them sound like they should.

The chip has 4 DMA-driven 8-bit PCM sample sound channels. Two sound channels are mixed into the left audio output, and the other two are mixed into the right output, producing stereo audio output. The only supported hardware sample format is signed linear 8-bit two's complement. Each sound channel has an independent volume and frequency. Internally, the audio hardware is implemented by four state machines each having eight different states.

Here is the pinout of Paula which I finally found after a long search...

Code: Select all

  1  b DRD24     DRAM Data Bus Bit 24    | 30
  2  b DRD23     DRAM Data Bus Bit 23    | 31 i CCK       Colour Clock
  3  b DRD22     DRAM Data Bus Bit 22    | 32 i CCKQ      Colour Clock Quadr.
  4  b DRD21     DRAM Data Bus Bit 21    | 33 o RIGHT     Right Audio Out
  5  b DRD20     DRAM Data Bus Bit 20    | 34 o LEFT      Left Audio Out
  6  b DRD19     DRAM Data Bus Bit 19    | 35 i P0X       Joystick 0 X Pot
  7  b DRD18     DRAM Data Bus Bit 18    | 36 i P0Y       Joystick 0 Y Pot
  8                                      | 37
  9  b DRD17     DRAM Data Bus Bit 17    | 38 i P1X       Joystick 1 X Pot
  10 b DRD16     DRAM Data Bus Bit 16    | 39 i P1Y       Joystick 1 Y Pot
  11 i _RST      Reset                   | 40 i _DKRD     Floppy Read Data
  12 o DMAL      DMA Request             | 41 o _DKWD     Floppy Write Data
  13 o IPL0      {Interrupt              | 42 o DKWE      Floppy Write Enabled
  14 o IPL1      {Priority Level         | 43 o _TXD      Serial Transmit Data
  15 o IPL2      {Bits 0,1,2             | 44 i _RXD      Serial Recieve Data
  16                                     | 45 b DRD31     DRAM Data Bus Bit 31
  17                                     | 46 b DRD30     DRAM Data Bus Bit 30
  18                                     | 47
  19 i _INT2     Interrupt 2 Request     | 48 b DRD29     DRAM Data Bus Bit 29
  20 i _INT3     Interrupt 3 Request     | 49 b DRD28     DRAM Data Bus Bit 28
  21 i _INT6     Interrupt 6 Request     | 50 b DRD27     DRAM Data Bus Bit 27
  22 i RGA8      Register Addr. Bus 8    | 51 b DRD26     DRAM Data Bus Bit 26
  23 i RGA7      Register Addr. Bus 7    | 52 b DRD25     DRAM Data Bus Bit 25
  24 i RGA6      Register Addr. Bus 6    |
  25 i RGA5      Register Addr. Bus 5    |
  26 i RGA4      Register Addr. Bus 4    |
  27 i RGA3      Register Addr. Bus 3    |
  28 i RGA2      Register Addr. Bus 2    |
  29 i RGA1      Register Addr. Bus 1    |
Anyone else thinking this would be a great project?

Sadly my electrical engineering skills are far too poor in undertaking the hardware design so I'm hoping to plant a seed here and see if there are more people who'd like to have a hw-based tracker player based on the Paula chip and a Raspberry Pi.

wire diagram for the chip

Audio programming on the Amiga and Paula ... e00D5.html
Raspberry Pi - finally a worthy replacement for A500!!!

Posts: 5
Joined: Mon Jan 18, 2016 11:36 am

Re: Paula (MOS8364) tracker player idea

Tue Apr 17, 2018 3:42 pm

This really sounds like a great project. Your post is quite old. Stumbled on it just now. Did you success in trying to build such a hardware tracker-player?

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