The DC2N diary-News archive, December 2006
02 Dec 2006
Libraries grow
Evening: I worked at the Linux version of the tap library, which is now a multiplatform one. The demo
application using it was built under Linux as well. It will be virtually able to put any data inside CBM/turbo
blocks within TAP files to use with DC2N too.
07 Dec 2006
Transfer to tape
Morning: I saved the head adjustment program to a tape with my C2N and PTap. I also saved a copy of the TAP
server program to use in conjunction with MTap/PTap, after storing it as a CBM block inside a TAP file.
I can now check what my C64 receives from DC2N while the latter is PLAYing a TAP file. I will first add one of the
cardedge connectors I bought to connect DC2N to my C64.
Evening: I used Star Commander to save all my disks to D64 images as well.
10 Dec 2006
New tests
Evening: I suspect the PLAY test was probably unsuccessful due to a hardware interfacing mistake rather than
a firmware problem. The tape head alignment tool and some voltage measurements seem to confirm this suspect of
mine.
Well, now I need to give a look at the tape port schematics of Commodore computers and tape recorders. Better
than what I was fearing when I did the PLAY test the first time, for a single pullup resistor may solve the
problem.
Since I have the tape connectors, I will also try to power the whole circuit with the +5V coming from the tape port
of my C64. I plan to build a nice cable instead of putting the connector directly on the DC2N circuit board.
I tried the dump feature again and this time I imported side 1 of "Skull & Crossbones"! After I
converted it to a legacy 8 bit TAP, all the 10 files (8 CBM + 2 TDI) were recognized by TAPClean and there was
no read error at all!
The 16 bit TAP file is available here. The new format header
was stripped since the tool to convert 16 bit TAP files to legacy TAP ones doesn't support it yet.
The legacy 8 bit TAP file is available here.
11 Dec 2006
PLAYing back tap files
Evening: It was with tears in my eyes that I watched to tapes being loaded by DC2N on my C64 after I realized
the tape connector had to be turned upside down. During the first PLAY test I had connected the probes to the tape
connector in the wrong order as well. That's the reason the first test did not work at all. Shame on me!
Here we go: some screenshots taken with my webcam (sorry about the quality!)
Btw, another tape was dumped: "Ultimate Combat Mission". All the 8 files (4 CBM + 4 Freeload
clone) were recognized without any read error! I think this will stay unnoticed for a while ;)
12 Dec 2006
Do it again
Evening: I took additional pictures while loading TAP files from DC2N. Many thanks to c64heaven for
his TAP imports.
16 Dec 2006
Another milestone
Morning: I built the motor signal adapter circuit and I changed the firmware to support the motor signal
too, so that the playback is now interrupted when the motor signal is low and resumed once it's high again.
The actual hard-PLAY feature acts nicely: all I need to do is to select a TAP file and the C64 will do the rest,
I do not need to STOP the DC2N. Of course, it is not wise to use this feature with poorly coded programs that do
not handle the motor signal as they should.
The hard-PLAY mode in action: the motor was stopped at the FOUND message
The whole DC2N circuit is now complete and powered by my C64 as well, thus resulting into a standalone device.
It's time to try the first builds of the DC2N firmware itself, which will gradually substitute the "DC2N
SD Card Suite" development.
17 Dec 2006
Analysis
Morning: I noticed some wrong values inside the char maps of the loading pictures of "Back to the
future 2" published on this page. I tried to reload that TAP file to see if it was happening at randomic
positions and I found out it's not randomic at all. The wrong chars are always the same.
If my memory serves me well, I had a similiar behaviour on my C64 with the original tape, but the TAP file
loads fine in VICE, so I will have to face this new issue.
Wrong values in the char maps of "Back to the future 2" hires
I tried to load the whole file within the Head Tester tool and everything looked ok. I guess loading the
original tape on a C64 would help a lot.
Btw, I tried to load "Shadow Warriors" and "The Blues Brothers"; they loaded just fine.
I was also able to play them a bit.
18 Dec 2006
Counting
Evening: the firmware now supports the "zero counter" button as well. I won't need it until I
implement the REWind and FastForWarD button handlers, which will happen shortly.
Btw, I loaded "Spooky Castle" and "Magic Carpet" with DC2N. This crappy joystick of
mine didn't help a lot while playing them.
19 Dec 2006
Prototyping
Morning: I gave form to the PCB of the prototype. It looks like this:
DC2N prototype (under construction)
The connectors won't be soldered directly over the PCB, but there will be cables for that connection, departing
from where those connectors sit in the above pictures.
Btw, that one is not a battery, it's a 50 pence coin ;)
Afternoon: I mounted the RS-232 conversion circuit too, so that I'm not using the one on the evaluation
board anymore. Here's a shot of my breadboard with some notes:
DC2N circuits on my breadboard
What's it all about?
| A - LCD module | BUS, trimmer, and LCD itself |
| B - "reset counter" switch | just a switch |
| C - motor signal adapter circuit | two resistors and a transistor |
| D - UART/RS-232 converter | MAX232 and the 5 Tantalum capacitors |
| E - adaper circuit for the SD Card power | the LM1117T3.3 and two capacitors |
| F - save LED circuit | a led and a resistor |
| G - SD Card module | BUS, resistances and the SD Card socket) |
Evening: I soldered almost all the components on the PCB and I created a few paths as well (the LCD module
is fully connected to the microcontroller).
While I was checking the problem with "Back to the future 2" I recognized that the signal generation
just before a TAV v 0 overflow pulse confuses Cyberload FT3 loader (while reading the last data bit) and possibly
any loader where trailing pulses are not used. I checked VICE, with which the TAP file loaded fine, and I can
say it worked well because VICE handles overflow pulses as normal pulses, instead of a constant 0-level.
I changed the firmware slightly and things worked just fine:
I don't think there's too much I can add: DC2N was designed to be compatible with the real C2N and any turbo
loader ever designed for Commodore homecomputers. It should be possible to remove any incompatibility by
pre-filtering TAP files, if any is found not to work, of course.
The tests will tell us more about that. I'm sorry no prototype will be ready before Xmas as I expected. One
would be already mounted if I would not have done that interfacing mistake during the first PLAY test.
22 Dec 2006
Playing
Morning: I loaded and played "Last Ninja 2". I reached level 3 where I lost all lives in those
damned passageways. My memory didn't help a lot. :)
23 Dec 2006
FFWD
Morning: I loaded and played "Turrican", "Turrican 2", and "Creatures". I
proceeded pretty well to higher levels and no problem has been met with DC2N. Playing them on the emulator first
helped a lot ;)
Evening: I implemented the FFWD feature and I did some major changes which will require some more testing
before being made official.
24 Dec 2006
More good news
Morning: I loaded and played "Turrican", "Turrican 2", "Last Ninja 2",
"Last Ninja 3", "Turbo Charge", and "X-Out". No problem has been met with the
new firmware.
Btw, merry Xmas to everyone!
26 Dec 2006
Turbo Tape
Morning: I loaded and played "Crazy Cars III", "Giana Sisters", and "R-Type".
I think these could have been the most problematic tapes, due to the loader they use, but they loaded just fine!
27 Dec 2006
PRESS PLAY ON DC2N
Morning: I loaded "Indy Heat", "Deliverance", "Ivan Iron Man", and
"Turtles" (Coin Op). To pass the protection screen of the latter, I patched the TAP file to change the code
itself, for I lack the AR cartridge on the C64 I use to test DC2N ;)
I cannot exclude I will produce a few trained TAP files but I won't distribute copy-protection-removed programs.
This reminds me about my parallel activities for Hokuto Force ;)
I worked at a new version of the firmware. It's even more friendly now.
28 Dec 2006
Timeless classics
Morning: This morning I played my trained TAP version of "Last Ninja 3". The game was fully played
to the end sequence. No problem has been met (the unlimited lives helped a lot :D).
31 Dec 2006
New instruments
Morning: I'm trying a different software for Schematic and PCB development, here there's a version of the
PCB I produced:
DC2N PCB
Btw, happy new year to everybody!
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