On Monday 07 May 2012, you wrote: > Hi, > > On Mon, May 07, 2012 at 06:25:29PM +0200, MichaĹ‚ Pleban wrote: > > >I also thought about it, since I've started to play with interfacing > > >with SD card on SPI bus, currently only through PC parallel port (to > > >"play" with it and some studies for myself), but I'd use a > > >microcontroller with dedicated SPI capability (btw, I also thought > > >about using ECN28J60 which is a 28-pin SPDIP ethernet controller with > > >SPI bus - it's really cheap, and not so slow, even 20MHz SPI connection > > >is OK for it -, maybe easier to play with it for a hobby user like me, > > >without heavy SMD, etc soldering and PCB designing capaibilities). One > > >question came into my mind however: I would hate to use > > > > >an EPROM just for bootstrap. It would be interesting to see this works: > > Well, I don't want to use any microcontroller for the simple reason > > that 6502 is the only processor I know how to program :-P > > I can understand you :) My only reason: interfacing with SPI bus is not so > fast if some "bit banging" is used, and I wanted decent performance mainly > because of the SPI based ethernet controller. However I am thinking on this > still, as maybe serial shift register of the CIA can help here to speed > things up a bit. In my idea uC is only needed to have some kind of fast > SPI/serial converter (and also to "cache" some data inside the uC's memory > still C64 is ready to process it, etc). > > However as far as I can see, the goals are a "bit" different, you may not > need this at all. i would strongly advice not to use the 6510 for bitbanging - since that is dead slow. look at what speed the mmc64 can offer, it has a small spi controller with 8mhz spi clock (so one byte can be transfered each c64 cycle), and also uses a huge unrolled loop to read a sector from sd card. this is quite ok speed, but already on the slowish side of things. with bitbanging it would be at least 10 times slower, if not more - and unrolling loops would be out of the question because codesize would explode. Message was sent through the cbm-hackers mailing listReceived on 2012-05-07 17:01:11
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