Thread: SD card adapter
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Old 14 September 2014, 12:35   #49
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Join Date: May 2006
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Originally Posted by JimDrew View Post
Paula only handles flux data, and there are many patterns that you can not use. Paula samples data at a maximum of 2us per bitcell, which converts to either 10, 100, or 1000. However, those values require 4us/6us/8us bitcell times with the Amiga format. It's not even remotely close to serial data, it's a disk controller. So, yes there are limitations, like you can't write more than three consecutive 0 bits in a row. Writing more than three 1 bits in a row is interpreted as a 00 byte, etc.

To use the floppy port you would have to emulate a flux data stream. There are always two bytes of MFM data required to extract a single byte of usable data. If you could just send serial data, we wouldn't need FM, MFM, GCR, or any other type of encoding method - we would just write the byte to the disk.

The Amiga serial port is pretty slow. I wrote several serial device drivers (in assembly of course) and the same core driver worked fine at 230400 baud with EMPLANT's serial port on a stock A2000, but the Amiga serial port would barely do 115200 baud.
So if you've an Emplant board on your Amiga it'll be faster right?

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