My hardware project :: GCart 2011

Modding and Technical Issues

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TLovskog
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Post by TLovskog »

Hi Mike,

Hmmm ... your comments got me thinking ...

Even better would perhaps be to swap b4 and b5. So b0-b3 selects one of the 16 banks of color ram, b4 is the guard bit and bit b5 selects upper or lower 16 banks from the total 32. As such one doesn't have to fill the colour information twice, can still use all memory if you want and use the simple INC xxxx instruction.
BR
Thomas Lövskog
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Post by Topiux »

Thomas,

+1 for this project. Count me in as a buyer + tester + Any way I can contribute (i.e. I can do some machine code programming).

Thanks for such a great initiative!
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TLovskog
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Post by TLovskog »

Thanks Topius!

It does go forward, but painstakingly slow. Mostly because it takes time and patience to solder all the 0.5mm pitch components ... time that is scares. I am considering to move to the next level of DIY and not only have the PCB's professionally created, but also mounted.

I have done the basics for one board to test the DC/DC converters, bus drivers and the in-circuit programming of the PIC and Xilinx CPLD.

The VIC-20 starts with the board plugged in ... that should count for something.

Image

Next week the board for the internal 8k should arrive, and they are a bit quicker to solder.
Last edited by TLovskog on Thu Dec 19, 2013 4:15 pm, edited 1 time in total.
BR
Thomas Lövskog
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TLovskog
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Post by TLovskog »

While waiting for a friend of mine with some real gear to finish up two more prototypes, I have soldered the Internal 8k board.

Didn't smoke when tested atleast. Now it needs to be fitted in one of my VICs ...

Image

... and the CPLD programmed of course.
Last edited by TLovskog on Thu Dec 19, 2013 4:15 pm, edited 1 time in total.
BR
Thomas Lövskog
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Post by joshuadenmark »

Hi Thomas

Thank for your update about this fantastic project.
I am glad to hear that the vic boot with the board attached :)
Last edited by joshuadenmark on Sun Apr 15, 2012 9:26 am, edited 2 times in total.
Kind regards, Peter.
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joshuadenmark
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Post by joshuadenmark »

No smoke! Thats great :wink:
Last edited by joshuadenmark on Sun Apr 15, 2012 9:25 am, edited 1 time in total.
Kind regards, Peter.
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Mike
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Post by Mike »

Hi, Peter,
joshuadenmark wrote:[...]
is it really necessary to quote the preceding two postings of Thomas in full, including pictures?
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Post by joshuadenmark »

Hi Mike, hmmm no not really :wink:
Kind regards, Peter.
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TLovskog
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Post by TLovskog »

2 complete (except WiFi module, OLED and some switches) prototypes built and initially tested.

Now it is time to implement some real software.

Image
Last edited by TLovskog on Thu Dec 19, 2013 4:15 pm, edited 1 time in total.
BR
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Post by MicroPet »

Sorry for the inane questions but I've gone through this thread and I'm kind of lost!

What are the features of this cart? Does it supersede any of the carts already out there (FE3, MC etc). Is there a realistic ETA, will it be for sale and is there a price in mind?!

Again, sorry if this is all covered elsewhere I just got lost in a mire of techno-talk. :)
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TLovskog
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Post by TLovskog »

MicroPet:
Sorry for the confusion and the inability to describe this project in a clear manner.

Some of the confusion might be because there are actually 2 projects in this thread. There is the Cartridge called GCart 2011 (To put a year there was quite dumb I admit) and the GCart 8k Internal board. These are totally different and can work independently, but the cartridge will recognise it and ease the configuration and use.

The GCart 2011 features are ...
Memory expansion. It handles all variants including 3k. The maximum memory (so far) that can be provided is 1Mbyte. All this memory is then mapped through menus to any block.
SD Card. You can ad an SD card up to 32Gbyte to be used as a disk-drive. Up to 4 simultaneously drives can be emulated.
WiFi. The cartridge contains a WiFi part so the VIC 20 can access the internet. It is intended to be used to directly load software from the internet using (as an example)

LOAD "ftp://some-site-with-vic-20-stuff/a-program.prg"

You can also access the SD card via a builtin ftp/web server.

You can also mount a diskimage on the internet to one of the virtual disk drives. Using MOUNT "http://some-site.com/a-diskimage.d64" TO U8

Audio decoder. There is a decoder for MIDI, MP3, FLAC, WAV, OGG, etc. The signal is routed through the cartridge port to the usual VIC 20 audio output, IF the VIC-20 in question has the updated motherboard that has this feature.
RTC with battery backup.
OLED Display. The display will show various information. Not really needed.
Reset switch.
Extended BASIC. An extension to BASIC and KERNAL (of 24k) that is used to set-up the cartridge, and manage the disk emulation. It also contain a few of my old extensions.

The GCart 8k Internal features are ...
Internal 8k RAM. This will provide 3k extra to the VIC-20 that are accessable for the VIC chip. This means you can a bit easier have more memory for video.
Additional color RAM. There are 32 banks of RAM for the color RAM. This will enable video modes with higher color resolution than normal. See Mikes eminent hardware modifications.

Compared to the other carts ...
I think it complements the others and does some things in another way. I have also done this from what I would like to have and something that has not been done before or in another way. To learn and have fun. If it then also suits others, all the better.

Below is my interpretation of the differences. Please note that I really do not own a FE3 nor a Mega-cart so if I am wrong here, let me know.

Mega-Cart has a plug-and-play repository of a huge number of carts and tapes. Many of which, as I understand it, have been fixed in some way or another. It also has RAM expansion for all banks.

GCart 2011 comes totally empty, except for the BASIC and Kernal extensions and possibly some of my own older software.

FE3 has similair massive SRAM and the SD Card / DiskDrive emulation.

The differense when it comes to the diskdrive emulation is that the FE3 actually emulates a Disk drive physically and thus works 100% (give or take) with multipart disks, demos etc. My cart works by writing directly to the RAM. That means that well behaved program (that use the KERNAL calls) will be loaded as fast as the 6502 possibly can write to the memory. A 8k program will then load in 30-40mS (exclusive overhead to set up the transfer). However if a multipart program uses custom routines it will fail.

FE3 also have a flash memory. GCart 2011 relies solely on the SD Card for non-volatile software storage, actually also including the BASIC and KERNAL extensions, bootloader, etc.

Availability and cost ...
I am working with the first prototype of hardware. So far it seams to work, but I have not really tested all the features of the hardware. I have found a few stupid misstakes (a wrong inductor in the DC/DC converter and I missed 2 capacitors in the clock source for the RTC chip.)

The software part is the big thing.

If I have a V1 available this year I will be glad.

If there are interest once it is finished than I am all for having a few ones fabricated professionally. In that case they will be bare boards, tested, but without casing (I will use a normal brown commodore case). Possibly I will have a custom made front foil because of the LEDS, OLED and switches.

Price depends very much upon the number of units produced. Today the prototypes costs 150-200 EUR, but much of that is eaten by the rather expensive 4-layer board in prototype runs.
BR
Thomas Lövskog
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Mike
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Post by Mike »

TLovskog wrote:Internal 8k RAM. This will provide 3k extra to the VIC-20 that are accessable for the VIC chip. This means you can a bit easier have more memory for video.

Additional color RAM. There are 32 banks of RAM for the color RAM. This will enable video modes with higher color resolution than normal. See Mikes eminent hardware modifications.
... which are found in the thread about my VFLI mod. :)

Greetings,

Michael
MicroPet
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Post by MicroPet »

Thanks very much for your informative reply. That makes things a lot clearer to me. :)

It does sound interesting and I'll continue to follow this thread with a slightly more informed frame of mind.

Good luck with the feature implementation. I quite like the idea of a Vic being used as an MP3 player and the online virtual disk stuff sounds intriguing!
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tokra
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Post by tokra »

Really looking forward to the GCart 8k Internal - if this enable VFLI-modes without the need for soldering, I'm sold already :-)

Just out of interest: Do you think the 6502 ROM/RAM expansion would also allow for the VIC to address BLK0 completely?
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Mike
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Post by Mike »

tokra wrote:Do you think the 6502 ROM/RAM expansion would also allow for the VIC to address BLK0 completely?
No, it wouldn't. It's on the 'wrong' side of the address/data bus buffers.

As Thomas wrote earlier in the thread, even though the GCart 8K Internal plugs into the character ROM socket, there still need some wires be soldered to the mainboard (and also some traces cut). Presumably still easier to perform than the VFLI mod, but then that one also doesn't require a PCB at all. ;)
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