JAMMArcade.net – Page 244

C64 breadbin JiffyDOS dual boot

Nov 122011

Today I finished my adapter to make a breadbin 64 accept a 27C128 EPROM.
The standard kernel ROM is a 2364 pinout and is 64Kb. To fit both the original kernel and the JiffyDOS kernel on obviously we need a ROM twice the size.
The problem is the 2364 is not compatible with any EPROM pinout unlike the C64c so this adapter is necessary.

I used 2 turned pin sockets, a 24 pin and a 28 pin one.

On the 28 pin socket cut pins 20, 23 & 26 short,not completely off but short enough not to make contact with the pins on the 24 pin socket when pushed together.
Connect pin 1 to pins 27 and 28
Connect pin 14 to pin 20

Get the 24 pin socket

Connect pin 28(VCC) of the 28 pin socket to pin 24 of the 24 pin socket
Connect pin 2 of the 28 pin socket to pin 21 of the 24 pin socket
Connect with 23 of the 28 pin socket to pin 18 of the 24 pin socket
Attach flying leads from pins 14, 26 and 28 of the 28 pin socket, these will go to your switch.
You can also fit a 4.7k resistor between pins 26 and 28 which means you don’t need that extra flying lead from pin 28 to the switch, just makes it that little bit easier.
Mash the two sockets together lining pin 14 of the 28 pin socket to pin 12 of the 14 pin socket.
Fit your 27C128 eprom and you should be good to go.

My first attempt works well but isn’t the neatest. If I make another and I almost definitely will, it will be neater.

C64 Easyflash cartridge

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Nov 102011

Got a little free time today to mess with my Easyflash cartridge for the Commodore 64.
The main reason for getting this was to play Prince of Persia but its a fantastic device that ill be using for playing many games.

Mine came with the new Prince of Persia game already flashed onto it but wanted to have a play around myself.
The reprogramming is all done via the C64 itself using the Easyprog program so no external programmer is required although an SD device is highly recommended.

If your using an SD2IEC device then the Fastloader option needs to be disabled in the OPTIONS menu or it will hang at this screen (thanks for the heads up Steve).

My mate Stiggy has already written a nice little writeup on this device and he stated that flashing a file took him just under 40 minutes. Not totally sure how big the file was but I tried to copy Last Ninja 1 & 2 over which is 882KB and using JiffyDOS took just under 10 minutes.

After this the game loads pretty much like you would expect from a normal cartridge. Im very impressed with this thing. Now to find more goodies to try out.

Loading times with JiffyDOS

General 1 Response »

Oct 302011

This post is mainly to make Stiggy drool a little.
It shows the loading times difference between the standard C64 kernel and JiffyDOS using the SD2IEC.
The videos show Last Ninja 2 loading from the FB64 program on a C64c. Try to ignore all the crack screens etc and take note of the actual loading screens.

Standard C64 kernal

Using JiffyDOS

C64c Original/JiffyDOS dual booting

General, Guides Comments Off

Oct 292011

Sometime back I modified my C64c with a switch to change between the original kernel and the JiffyDOS kernel. I did this because JiffyDOS is incredible for loading games from the SD2IEC but it doesn’t support loading from tape at all.
I needed to make another one up. Turns out I forgot how to! so here it is mainly for my own sanity.

Get a 27C256 eprom
Get a copy of the original C64c kernel. This should be 16KB in size, if its 8KB then that’s from the older breadbin C64.
Get a copy of the original C64 basic ROM. This is number 901226-01. This should be 8KB in size.
Get your copy of JiffyDOS for the C64. This should be 8KB in size.

Place all these files in a directory and open a command prompt (assuming your using Windows).

I renamed my files to something a bit more meaningful, “kernel.bin” “basic.bin” and “jiffy.bin”.
Type the following command:
“copy /b kernel.bin+basic.bin+jiffy.bin new.bin”

This creates a new binary file called “new.bin” and it should be 32KB in size.

Burn “new.bin” to a blank 27C256 eprom
Lift up leg 27 of the eprom so it doesn’t make contact with the socket pin.
Solder the common leg of a switch to pin 27
Solder one side of the switch to a 4.7k resistor connected to +5v
Solder the other side of the switch to GND

This should now give you a fully working switchable C64c.

Note: This only works for the newer C64c version. A 27C256 eprom isn’t pin compatible with a breadbin version without more modifications.
Also, JiffyDOS is still being sold and is not downloadable from my site nor will I provide it to anyone asking.

ZX Spectrum repair log #2

Computer Repair Logs, Repair Logs Comments Off

Oct 222011

The second of the ZX Spectrums I got recently, which is motherboard only, gave absolutely nothing on the screen
Replaced the usual ZTX650 for a ZTX651 and the one next to it which is a ZTX213.
This one also had the capacitor above them missing. Replaced this for a 4.7uF 50v one and tested.

All working again

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