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 Flash 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 update 04 Sep 2008 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 TAP files is being tested RECORD and Dump  DC2N 16-bit TAP 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 the 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 board. Once a valid file has been selected, it can be played 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 single 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. 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.
Ordering
	The first batch of DC2Ns has been already shipped to large collectors who had interest in having a DC2N quite some time ago, for preservation purposes. A second batch of devices is being built right NOW. Pre-orders for DC2N are closed. Sorry. Pre-ordering will be possible again as soon as possible. Please do not ask about the price for I do not yet know how the third batch will be manufactured. The actual price is around 45 UK pounds (components were bought from USA and in UK). DC2N is sold on a first-come-first-served basis. If you think you should be on the pre-order list below and you aren't, or if you are there and you don't want to be anymore, email me. People who have pre-ordered so far (I am waiting for authorization to publish all names): Firstname Lastname Country Order status Nigel Parker UK Complete Thomas Karlsen Sweden Complete Niels van Dijkhuizen Netherlands Cancelled by buyer Stefan Termén Sweden Complete Robert Lyons UK Complete (kit) Martin Pugh Wales   waiting for consent waiting for consent waiting for consent   Rene Szvasztics Austria Complete (kit) waiting for consent waiting for consent waiting for consent   Severin Stefan Kittl Austria   waiting for consent waiting for consent waiting for consent   Mats Johansson Sweden   Erik Holstensson Sweden   waiting for consent waiting for consent waiting for consent   --- Sorry None Left on Sale! ---
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.
Production
	DC2N 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: coming soon DC2N PC-side Software: dc2nconv Description: this tool converts DC2N 16-bit TAP files to legacy TAP files. The Windows version comes with a Shell Extension to integrate the conversion process in Explorer. Download: Linux binary (Debian Linux) - Win-32 binary TAP Studio win32 DEMO - DC2N edition Description: this tool shows data inside DC2N 16-bit dumps. Download: Win-32 native binary MS-DOS batch file to convert TAP files to version 0 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: MS-DOS batch
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 = Commoodore 16 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 0x14 any 16-bit (counter resolution) data values (LSBF) 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 the name on the SD card doesn't 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 to 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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