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Post by eslapion on Jan 4, 2020 6:42:27 GMT
If you recall, the VDC RAM is a bit of a 'walled garden'. Having an interface to the (faster) RAM would allow it to be accessed by another entity other than the VDC and at a higher speed.
Im thinking cartridge memory space, REC chip, etc.
Basically, the VDC RAM could be used as a double/triple screen buffer while the actual VDC just 'shifts' the data out. (The REC can even be used as a sort of blitter chip with some scope for better software sprites).
I know it would be some work to interface, but, hey, Im just saying thats what I would like! I think both a REU cart and a final chesscart could make for some interesting scenarios with this sort of hack. Yeah, that makes sense but DPSRAM is still awfully expensive. The SRAM I put on SaRuMan-VDC exists in much faster variety, as fast as 12ns. It would be more technically complex but considerably less expensive to allow access to the same SRAM between the cycles used by the VDC and also during the HBI and VBI. The loss in speed wouldn't be much. I know Gideon Zweijtzer (64 Ultimate and 1541 Ultimate) created a VHDL version of the REC which uses SRAM.
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Post by eslapion on Jan 3, 2020 19:04:15 GMT
What Ive always wanted to do is a '68 version of this, fitted with dual ported VRAM with some form of easy interface connector for future hacking purposes! If I had the earlier VDC (or infact ANY working 128 machine! lol) I would buy this. Its very reasonably priced. Great work! The '68 is used on the C128DCR which already has 64k of separate VDC RAM so I don't get the point. Also, dual port RAM could potentially be useful for greater speeds on the C64 and VIC-20 where RAM can be shared between the CPU and video chip but the VDC has RAM all to itself so what could possibly be the point of having dual port RAM with a VDC ?
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Post by eslapion on Dec 29, 2019 11:11:30 GMT
The price tag is 17$US or 15 Euros per unit + shipping.
Quantity discounts available for 5 units or more.
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Post by eslapion on Oct 22, 2019 18:48:19 GMT
All my boards sold pretty quickly so I got another 30 units made and they just arrived!
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Post by eslapion on Oct 8, 2019 8:42:26 GMT
Download expired! :-(
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Post by eslapion on Oct 7, 2019 17:06:00 GMT
That's pretty cool. Do you have actual figures for the power use for that Vs DRAM chips? It would be interesting to see! I love the new board though, if I didn't already have an upgraded machine I would get one! I didn't check the datasheet of 64k x 4 DRAM ICs to see how much power they use but the SRAM used on SaRuMan modules consumption is around 1.3mA according to the datasheet. The additional logic consumption is around 2mA. This is extremely low power. A single LED takes around 20 times more.
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Post by eslapion on Oct 7, 2019 6:03:24 GMT
4 units in stock!
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Post by eslapion on Jul 15, 2019 18:44:53 GMT
400 units sold!
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Post by eslapion on Jul 15, 2019 8:08:17 GMT
Thats pretty cool. Where is it going to be sold? Here and Now!
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Post by eslapion on Jun 27, 2019 17:11:53 GMT
Thats pretty cool. Where is it going to be sold? On various forums and here. Pricing at 18$US per unit. Just send me a PM once we have a few boards out of the fab. Forgot to mention there will also be a version of this board which will provide 64k expansion for the Commodore 16 internally. A very small board you slide under the TED and it will work with ALL versions of the Commodore 16 and cost 18$US (15 Euros) too. The version for the C64c is presently available at the same price.
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