On Tue, May 08, 2012 at 05:51:03PM +0200, MichaĹ‚ Pleban wrote: >For now, I think it would be best to use 512k SRAM and a CPLD. It could >be configured to handle the SD-card interface, or even reprogrammed to >emulate the REU or whatever. I think this way it will be much more >flexible. Right, implement a REU-like device that would additionally speak with the SD-card. Use a small EEPROM for bootstrapping. The C64 would tell the REU-like device to do transfers between SD and on-cart RAM, or between on-cart RAM and main RAM. Last time I looked (several years ago), Atmel had some combination of AVR and programmable logic. I wonder if that could be useful for implementing the SD interface. Also, I have been suggested that some microcontroller+logic SoCs can be configured to look like a ROM chip from the outside. That could enable an almost single-chip solution. The same idea could be used on the Vic-20 and plus/4. At boot, bring in an 8k or smaller bootstrap ROM. Load a menu or whatever to RAM, and finally load the image, set up the desired configuration in both internal memory, on-cart memory, and on-cart I/O circuits (for emulating different bank switching cartridges and so on). I have been thinking about this. My Vic Flash Plugin with its 4MB 5-volt flash is a dead end. In theory, it hosts all the Vic-20 software ever written. In practice, it takes too long to reload the flash image when you want to change something. It would be handier to plug in an SD card. Even if the cartridge did not understand a full-blown file system, it would be fast to set up the images on the SD card on a beefier machine. Best regards, Marko Message was sent through the cbm-hackers mailing listReceived on 2012-05-08 18:00:38
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