DC2N - a Digital Datassette replacement for Commodore homecomputers

DC2N stands for Dumping C2N and it's basically intended to be a standalone system that lets its users dump (ie. make a digital backup of) their own old tapes without any PC OS/filesystem restriction as it has been happening until now. It is also a compact replacement for the tape unit used with Commodore homecomputers (C64, C16, VIC 20, PET) back in the 80's and 90's, the datassette. Finally, DC2N incorporates a tape duplicator that lets people save TAP files back to tapes using a datassette. Brilliant quality can be achieved now. I chose to provide such a replacement by using SD cards as storage medium. This implies many advantages: compactness, low-power consumption, and an almost endless time of operation, just to name a few. Many thanks to the persons who supported this project: Robert 'Peepo' Taylor (building, ordering, testing, and plenty more stuff), Bo Gøran Kvamme & Francis Rath (board prototypes), Tom Roger Skauen (testing, bugreport, & suggestions), Martin 'enthusi' Wendt (support), Fungus (ideas & support), Lars Pontoppidan (ideas), Romeo Cane (components), Nicolas 'X1541' Welte (info about where to order the expensive tape port connectors from USA), Richard Lagendijk & Ron van Schaik (HCC show in Holland), Nigel Parker (Commodore Free articles), and all the people who gave me a feedback as well. Luigi. e-mail me

Stats
	Last updated 18th June 2009 Completed 99.9% Tested 99.9% (the three main features: PLAY, RECORD, and Dump) FAT-16 support read: 100% write: 99% I developed a hard real-time implementation of the FAT-16 filesystem driver. PLAYback legacy TAP v0 files support for DC2N 16-bit DMP files is being tested RECORD and Dump  DC2N 16-bit DMP files (counter rate is 2 MHz) TAP version 0 files (100% MTap compliant)
DC2N in brief
	When used as a datassette replacement, connected to the tape port of a Commodore computer, the DC2N can play files that are stored on a SD card. In this mode of operation, the DC2N draws the power it requires directly from the Commodore computer it's connected to. DC2N supports the FAT-16 file system and for playback purposes it reads files in TAP format. A TAP file to play is selected by means of the LCD and pushbuttons on the DC2N device. Once a valid file has been selected, it can be played back by DC2N by pressing the PLAY pushbutton. Any tape loader is fully supported, including multiloaded tape programs. DC2N also features a FFWD function and the LCD shows a counter that comes handy when it is needed to seek any program on a multi-program TAP file. For recording purposes a different file format is used to save data to the SD card. This format has been defined by myself to allow an accurate representation of the data that is being saved. I also wrote multiplatform PC tools that allow easy conversion between the DC2N format and the TAP one. These are available below on this page. When used as a dumping system, an external PSU is required to power DC2N if you want to use it as a standalone device. In this mode of operation the DC2N format is used to store the tape contents on the SD card while it is being played by a datassette connected to the DC2N. Feature DC2N commercial version DC2N expert version Load TAP files from SD Card to C64/VIC20/PET Multiload games & programs Record data from C64/VIC20/PET to SD Card Dump tape to SD Card Duplicate TAP files from SD Card to tape Motor signal handling Counter & counter reset (optional) SAVE LED (optional) Debug SD Card I/O   Change request Submitter Status Support for playback of DC2N DMP files LDF OBSERV Boundary FAT condition support in write mode LDF OPEN When ejecting a TAP, selection of files could resume from that TAP LDF OPEN
DC2N pics
	DC2N (commercial version). DC2N (expert version) dumping a tape played by a Commodore datassette.
DC2N vids
Ordering
	DC2N is sold on a first-come-first-served basis. People who have shown interest in and pre-ordered so far: Firstname Lastname Country Order status Nigel P....r UK Complete Thomas K.....n Sweden Complete Niels van D........n Netherlands Cancelled by buyer Stefan T....n Sweden Complete Sebastian R.......i Germany   Robert L...s UK Complete (kit) Martin P..h Wales   Rene S........s Austria Complete (kit) Fabrizio G.....i Netherlands   Severin Stefan K...l Austria   Mats J.......n Sweden   Erik H.........n Sweden   Fulvio L...l ?   Per-Olof K......n Sweden   Henrik I.....i Sweden   Kenny B...n UK   Kai K.......i Finland   Addy van L........n Netherlands   Matt C...p Austria   Andrew L.......y ?   Sam S...h UK   Sönke R.......n Germany   Bruno ? France   Mark R......s UK   Pál P....k Hungary   Rikard L..g Sweden   Craig P.....r ?   Peter H......n UK   Jorma O.....n ?   Mark G.....n ?   John W....n UK   John Christian L........l Norway   Dominic M...r UK   waiting for consent waiting for consent waiting for consent   Richard G....r USA   Stephane S.....z Belgium   Ray G...n USA   waiting for consent waiting for consent waiting for consent   waiting for consent waiting for consent waiting for consent   waiting for consent waiting for consent waiting for consent   Mike T......l UK   Anton S.......r-M.......k Germany   To preorder email me your fullname, country where you live and be sure you use an email address that I can use to contact you and give you updates later on. If you think you should be on the pre-order list above and you aren't, or if you are there and you don't want to anymore, email me.
The Author
	I'm a 30 year old electronic engineer. I was born in Italy where I lived, studied and worked until the age of 28. I like to think that my country is too much ahead to make any profit out of myself, so that I decided to move to UK in March 2007 where I still live and work.
Firmware
	Bootloader Description: chip45boot ported to ATMega32. Some customizations were made to start the bootloader based on the bootloader jumper position. This program lets users update the DC2N firmware easily, by means of a serial port, with no need of specific programming hardware. Download: src (Makefile included) - hex DC2N BOST Description: this is a testing tool I made to discover if a new DC2N circuit was correctly built or not. Download: srec file with builtin LCD test (do not use if LCD is not connected!) srec file without builtin LCD test DC2N SD Card Test Suite Description: this is both a complete SD Card and C2N emulation feasibility test suite I am developing to deeply test the drivers I use (SD Card, UART, LCD, and FAT-16). Download: This program is licensed to single users and therefore not available for download. However, the license does not have any cost. DC2N Description: this is the DC2N firmware for C2N emulation, tape backup and duplication. Download: This program is licensed to single users and therefore not available for download. However, the license does not have any cost.
PC software
	dc2nconv Description: this tool converts DC2N 16-bit DMP files to legacy TAP files. The Windows version comes with a Shell Extension to integrate the conversion process in Explorer, as shown in the following image. Compliance: release 1.4 performs the DC2N format version 0 conversion with support for different machine types and video standards. However, only 16-bit files sampled at 2 MHz (DC2N defaults) are supported. dc2nconv downloads dc2nconv-rel-1.4.zip Windows (all versions) dc2nconv-rel-1.4.tar.gz Debian Linux TAP Studio win32 - DC2N edition Description: this tool shows data inside DC2N 16-bit dumps. It can convert dumps to TAP version 1 format (just as dc2nconv does) along with allowing very basic editing, like silencing noisy areas of the dump. TAP Studio win32 downloads tapstudio-rel-1.3.0-win32-dmp.zip Windows (all versions) MS-DOS batch file to convert TAP files to version 0. Version 0 TAP files can then be used in DC2N for playback to a real C64. Description: this batch file converts all TAP files found in the current folder to version 0. It has to be used in conjunction with TAPClean commandline. Download: tap-convert-rel-1.3-dos.zip
DC2N TAP format
	16-bit DC2N format generated by RECORD/dump operations respectively: 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 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 actually 0x10 4 bytes Counter rate (LSBF) [Hz]: 2000000 actually (0x80 0x84 0x1E 0x00) 0x14 any 16-bit (i.e. counter resolution) data values (LSBF). Each byte is MSbF. 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. DC2N TAP file resolution (2 MHz) is actually 16 times higher than the legacy TAP format (123.156 kHz).
F.A.Q.
	Q. When I save a file from the C64 why doesn't the filename on the SD card match the one I gave to the file? A. The filename you specify when you save from a Commodore computer with e.g. SAVE "MYPROGRAM" is not used as filename by the DC2N. I'll make an example to illustrate how complex this is. Let's think about a digital camera: it saves pictures as DSCF0001.JPG and so on, or some sort of incremental count inside the filename. When you take a picture of a tree, say in Windsor Castle, would the camera be able to name the picture "Tree in Windsor Castle.JPG"? That's the very same concept here. The filename given to a program is preserved inside the DMP file (and then the TAP file when converted by means of dc2nconv), but there's no point for DC2N to dig into what is being saved and extract the filename. That's why files recorded from a Commodore computer will be named DUMP0001.DMP, DUMP0002.DMP and so on. >---------------------------< Q. Which kind of external power supply do I need to use with DC2N to dump tapes? A. DC2N is a digital device so that it needs a stabilized power supply. 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 4.5 V DC PSU. That's been tested as well and it is fine provided that it is stabilized.

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