Posted By
Bionic
on 2004-01-07
06:19:34
|  Re: Sid-Card experiments
Well, I assume 40Euro is the lowest boundary, WITHOUT a SID. But I have to look into this later when I got a prototype on a custom PCB. The problem of low volume manufacturing is still unsolved..
The flash adds around 4-5Euro to the price.
Differences to Solders card:
-Runs at actual C64 SID clock (software configurable)
-More efficient voltage converter, hence a 6581SID can be used. But I have yet to test this with a real Plus/4 power supply.
-Supports emulation at $D400, so that frequency/wave converters can be circumvented. (software configurable)
-256kb or 512kb flash
-Uses more reliable handshaking (not relevant to enduser)
-No support for mouse/joystick/paddle..
-It is not possible to read the SID registers anymore, but this was probably a bit broken on the original card, too.
The flash can be accessed as the first external ROM bank, so it is similar to the 3plus1 software. This means it is unfortunately not possible to replace the internal kernal It is also not possible to use it as external RAM, as the flash is accessed pagewise. No single byte writes are possible.
I thought about inclluding an external 256kb memory extension. But so far I am not sure how to replace the internal memory with external one (may be possible, since this seems to be what the external 64kb extensions do). In addition it is not possible to maintain compatibility to solders internal 256kb extension as this would require cutting some lines on the Plus/4 PCB.
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