The DC2N diary-News archive, November 2006
01 Nov 2006
Wondered what's inside
Morning: I manually fixed the TAP file I dumped with the DC2N hardware. Those CBM files contain a
copy of the Turbo Tape program, which is loaded and executed transparently.
When I tried to clean this TAP file in TAPClean, I also pointed out an issue in the latter, during the
cleaning procedure: a few pulses do not get cleaned at all, even if they were correctly decoded. Those pulses
are unlikely to be found inside healthy CBM files, so it's not an urgent problem.
Thanks to a wonderful little tool, BootIt NG, I resized the system partition of my laptop and I created
a FAT-32 one that I will use to dump tapes with my C64 + 1541 cable and MTap. In this way I can test the
dump feature of DC2N against the one provided by MTap. I do not expect differences.
Besides, today I re-dumped the tape I have here and once again I got the same results: the CBM ROM file
that hadn't problems is ok in this dump as well.
Evening: I decided a small redesign of the MOTOR and STOP lines. To use the sleep feature of the MCU,
those signals will be attached to external interrupt lines. As we can see from the DC2N State Machine Diagram,
the main part of state changes are caused by changes of MOTOR and STOP.
"The flower": DC2N State Machine Diagram
By means of such a redesign, the MCU can be kept sleeping for the main part of operation (any state whose exit
condition is either a change in MOTOR or STOP will result in the MCU sleeping).
02 Nov 2006
A placeholder for my jewels
Evening: the SD Card USB reader is here and works perfectly with both my SD Cards and OS. This reader
will be very useful to speed up the FAT-16 test job.
I decided DC2N will access the "TAPS" folder on any valid partition found on the SD Card to let the
user pick up a TAP file to PLAY. Another folder may be named "D64S" and another "G64S"...
Unfortunately the monitor and X1541 cables will be sent to me just tomorrow, so I won't be able to test the
PLAY feature during the next weekend. Well, I will have some more time to find a way to plug the DC2N hardware
to my C64. Anyway, the day is closer.
03 Nov 2006
Shining jewels
Evening: I worked at the FAT-16 support. The firmware now enters the TAPS folder inside the mounted
partition, lists its contents, and is capable to open any of the TAP files for playback.
I may decide to let the user freely navigate within the WHOLE FAT-16 filesystem to pick up a TAP file to PLAY,
instead of just restricting any action to the "TAPS" folder. This includes handling subfolder and
parent folder navigation, which isn't that hard. We'll see what happens.
I chose to put some Cyberload TAP files on my SD Card, so that I will be able to know if the load process occurrs
correctly with a real C64.
Entering the "TAPS" folder and listing its contents
04 Nov 2006
Playback improvements
Morning: "DC2N SD Card test suite" fully supports PLAYing of legacy TAP v0 files. The overflow
value (0x00) now causes a delay during which the output is kept at 0V, just as it happens with a real C2N.
My TAP v0 files were converted from TAP v1 ones, so that the overflow value I'm assuming (20000 cycles) is
producing exactly the expected delays.
05 Nov 2006
Making a library
Evening: I wrote a TAP library which lets me convert PRG and PXY files into TAP files using the CBM ROM
loader. It will come handy when I will need to load PRG and PXY files on my real C64 from DC2N.
This library will also support turbo loaders if I can find the time to add any of them.
By the way, the cables were not sent in yet, but I found a way to use the C2N tape connector without breaking
anything. There's enough space for some probes over its contacts!
07 Nov 2006
Counting
Evening: a counter is now shown on the LCD while PLAYing a TAP file. It acts according to the model
I made for the C2N counter, getting slower and slower while the TAP file is being loaded. I don't know
if this feature will stay as it is; I may choose to use a counter whose speed is constant, to simplify the whole
thing. In fact, it has to act congruently while F.FWD-ing and REWIND-ing.
Thanks to bgk for his table of C2N counter <-> Time. I used it to estabilish the counter speed and its
variations.
The cables were sent to me yesterday. Hopefully, during the next weekend I'll be able to test the PLAY feature.
08 Nov 2006
Accurately counting
Evening: I compared DC2N and C2N counters. When my longest tape ended, the C2N counter read 324.5, the
DC2N one read 326.
Not bad, I will be to able reuse the counter values I wrote down when loading programs from multi-program tapes
if I will load them as TAP files with DC2N.
10 Nov 2006
New schematic
Morning: Thanks to Peepo and Nicolas we found the connectors needed to connect DC2N and C64.
Evening: I worked at the DC2N schematic again:
DC2N Schematic
I worked at the prototype PCB as well, to make it more compact:
DC2N prototype PCB (still under design)
Anyway I'd appreciate very much some help with the PCB design for I'm not used to such a design and I don't know
the good practices regarding this activity.
11 Nov 2006
PLAY mode
Morning: the very first PLAY test was done. I hooked DC2N lines to the C2N connector contacts and I excluded
the power and motor lines. It's not as clean as I wish, but this is just a test.
Honestly, I have no idea about what went wrong, but nothing was loaded by my C64.
Besides, my C64 hangs after a few minutes when I connect it to the monitor with the monitor port->SCART cable. When
I try to connect it to the TV in the sitting room by means of the RF output it doesn't hang at all. This will
require further investigation = additional delay.
I will transfer the tape head adjustment tool to my C64 and I'll look at what is received from DC2N. Anyway, I have
to fix the problem with the monitor connection first, for I need to have a working one to be able to try the DC2N
again.
Evening: I worked at "taplib", the library of routines to convert PRG/PXY files to TAP files. I
built a demo program that uses the library. It accepts a PRG file and saves its data into a TAP file as a
nonrelocatable CBM block. In this way I obtained a TAP version of the tape head adjustment tool I hope to be able
to transfer to tape by using PTap. I got to buy a tape before doing so.
13 Nov 2006
Boot
Evening: thanks to the feedback from its author, Erik, the bootloader is now working on my ATMega32. I can
update the firmware by means of the serial port and my terminal program: no programming circuit is needed anymore!
I think I will make the bootloader start depending on the position of a jumper on the DC2N hardware.
Well, I hope to be able to let betatesters help me with some tests soon. I will order the additional hardware we
need during the following days. Hopefully you will receive one prototype each before Xmas, mates.
This morning I ordered a standard monitor cable to be able to check the PLAY feature as well.
14 Nov 2006
Selection made easy
Evening: I made the TAP playback selection easier. TAP names are used instead of their index:
TAP selection for playback
I almost finished the prototype PCB design as well:
DC2N prototype PCB (almost finished)
I also made a bill of matherials.
25 Nov 2006
A new test is closer
Evening: The new cable to connect my monitor is here. I haven't any problem with its use.
I have a X1541 cable too so that I thought to transfer the head alignment tool to a disk instead of saving it to a
tape. I haven't the proper tools here yet, but I should be able to arrange the transfer soon.
I also bought a 60 min blank tape, just in case.
Hopefully, I will be able to understand what went wrong during the first PLAY test when I will be able to run that
tool on my C64.
27 Nov 2006
Hard times
Evening: I tried Star Commander, but unfortunately it doesn't seem to work with my laptop's parallel port.
I suspect MTap may have the same problem and I realize I haven't the right equipment to use it neither. This is the
point at which I would like to receive some external help.
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