Stereo to C64 with DualSID

I finally assembled one of my DualSID kits. It’s an add-on board for C64 that makes it possible to install an additional SID chip with several different configurations. Detailed description can be found at the DualSID home page or in my earlier post.

Update in April 2018: The DualSID home page is gone, so I add the latest(?) versions of the assembly instructions here, plus link to Lemon64 forums.

• dualsid_assembling_instructions_6581_v3
• dualsid_assembling_instructions_8580_v3
• Discussion, mods and fixes on Lemon64 thread

Note: the transistor orientation is incorrect in the pcb silk screen in pcbs prior to pcb v3. However, letters E, B, C are printed correctly on the board, so check your transistor pinout. Pictures seen on this post have the transistor installed wrong way around. Transistor’s flat edge should face towards edge of the board. I’ve fixed mine since. </update>

I made this one as the 8580 version. Here’s the board – without and with SID chips.

For the convinience of installing it from one C64 to another if needed, I made all external connections and jumper settings using pin headers. When the board is like this, the second SID address selection is done by setting the jumper block in the 2×4 pin header to correct position. Instead of manually changing the jumper block’s position, I’m able to replace the block with 2×4 female pin header that is wired to e.g. a rotary swithch. That way the changing of second SID address can be done externally.

EasyFlash fastloader comparison

Unseen has finally released a new version of the sd2iec firmware. This new firmware version of 0.10.2 does not bring that many updates, but one that I have been waiting for; sd2iec has now support for the fastloader that has been in EasyProg since ages.

I wanted to make a little comparison of the now supported fastloader’s performance using uIEC. Which is faster, EasyProg fastloader or JiffyDOS? Will it take even less time to flash the cartridge if the cartridge image is compressed using EasySplit?

Hardware & software configuration:

• C64E (new, short board) with JiffyDOS KERNAL, switchable between standard KERNAL and JiffyDOS 6.01
• uIEC/SD v3.1 with sd2iec firmware 0.10.2
• Standard EasyFlash cartridge
• EasyProg 1.5.2
• EasySplit 1.0.0

The image I flashed several times using different configurations was Prince of Persia C64 version 1.1. It is a 513 kb cartridge image, closely half of the flash memory size of EasyFlash. When the image is compressed using EasySplit, the file size is 159 kb. In Commodore terms, the images were 2069 and 644 blocks respectively.

Revealing Stats

People search for funny things on the Internet. Every now and then even my blog statistics display some curious search phrases. Today, when I had a look on my blog’s stats, this is what I saw:

I can only wonder why someone looking for Jeri Ellsworth nude has landed on my site. It must have been disappointment though, as I can assure that I don’t have any risky pictures of Jeri around.

Instead I can present you with some metaphoric retro nerd-porn involving Jeri in a different context. Behold, my C64 DTV signatured by Jeri – the creator herself!

C64 DTV hidden file showing the DTV-team.

How’s that for ya?

Also, I hope that the person trying to figure out if Commodore Amiga CD32 and Amiga CD32 are the same thing found an answer.