DC2N by Luigi Di Fraia DC2N - a Digital Datassette replacement for Commodore homecomputers


Description Media files Ordering PC Software FAQ
DC2N navigation pane by Luigi Di Fraia
This page has last been updated on: 10 Mar 2010.


DC2N DMP format specification:

Offset Size Description
0x00 12 bytes ID string: "DC2N-TAP-RAW"
0x0C 1 byte Format version: actually only version 0 is defined
0x0D 1 byte Machine for which the tape content is intended
  • 0 = Commodore 64
  • 1 = VIC 20
  • 2 = Commodore 16, Plus/4, etc.
This information is only used to convert to TAP format. Note that 2 is not yet applicable.
0x0E 1 byte Video standard for which the tape content is intended
  • 0 = PAL
  • 1 = NTSC
This information is only used to convert to TAP format
0x0F 1 byte Counter resolution [bit]: 16 in DC2N
0x10 4 bytes Counter rate (LSBF) [Hz]: 2000000 in DC2N (0x80 0x84 0x1E 0x00)
0x14 any 16-bit (i.e. counter resolution) data values (LSBF). Each byte is MSbF.

The DC2N format is used for RECORD/dump operations respectively. The DC2N DMP file resolution (2 MHz) is more than 16 times the one used by the legacy TAP format (123.156 kHz).

Each data value is the delay, expressed in clock cycles (at Counter rate), between two consecutive rising (falling) edges of the Commodore computer write line (C2N read line) signal.
0xFFFF is an overflow value, meaning that the next data values should be summed to this one to build up the total delay, up to the first non-0xFFFF value (included). Anyway, we don't really require to deal with that since the dc2nconv software converts DC2N 16-bit files to legacy TAP v1 files, which are already supported by many emulators and tools.


Power supply:

DC2N is a digital device so that it needs a stabilized power supply while dumping tapes. The required voltage is 5V DC. Power supply units that erogate 800mA, 1A, and 2A have been tested without issues so far.

In some countries it is easier to get a 4.5V DC PSU. That's been tested with different results: some PSUs are unable to erogate the required current, therefore the tape drive motor is slower than it should be and pulses have a longer duration than their nominal values. To be on the safe side, avoid anything that's not a 5V PSU.

2.5mm (inner)/5.5mm (outer) DC plugs fit into revision 2.0. The inner part has to be 5V, the outer one GND.

DC plug to be used in conjunction with the DC2N unit by Luigi Di Fraia

Polarity of the DC plug to be used in conjunction with the DC2N unit by Luigi Di Fraia


Serial terminal settings (optional):
  • baud rate: 57600
  • data bits: 8
  • parity: none
  • stop bits: 1
  • flow control: none
A terminal program can be useful to monitor data while dumping, as shown here.

The connection to a PC'serial port is made using a Serial RS232 9 pin Male to Female cable, NOT a null-modem one.

Serial RS232 9 pin Male to Female cable to be used in conjunction with the DC2N unit by Luigi Di Fraia

One end of the lead has to be MALE (it fits into the DC2N) and the other one has to be FEMALE (it fits into the PC serial port).

Comers since area creation: Since April 2002 - Best viewed at 1024x768


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