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Discussion - Hardware / ft245 (232 or 2232 in 245 mode) interface to 68000 bus?
« on: November 03, 2019, 12:45:38 PM »
Anyone have advice, or an example schematic connecting the 8 bit data bus end of an ft245 as an I/O device to a M68000? (or 6502 for that matter.)
I'm particularly interested in what buffering and what handshake signals, signalling DTACK and IRQ, would be needed, and using whatever modes would enable bi-directional buffering transfers rather than just bitbang and at the highest data rate possible.
This would be to allow me to connect a modern USB computer to an older 68k machine and be able transfer data back and forth.
I realize that on the 68k side I'd need some tri-state logic to detect the I/O address and enable the 68k data bus lines, as well as 5v<->3.3 conversion, but I'm less sure about the handshaking logic to the ft245 side. Ideally I'd like to be to write code on the 68k side to MOVEP bytes in a loop, one at a time, in or out and not potentially lose them. That is to use the internal buffer that the ft245 chips do, so on the modern PC side I could use the driver and read the same byte stream sent by the 68k or write a stream of bytes and have it delivered to the 68k side.
Thanks.
I'm particularly interested in what buffering and what handshake signals, signalling DTACK and IRQ, would be needed, and using whatever modes would enable bi-directional buffering transfers rather than just bitbang and at the highest data rate possible.
This would be to allow me to connect a modern USB computer to an older 68k machine and be able transfer data back and forth.
I realize that on the 68k side I'd need some tri-state logic to detect the I/O address and enable the 68k data bus lines, as well as 5v<->3.3 conversion, but I'm less sure about the handshaking logic to the ft245 side. Ideally I'd like to be to write code on the 68k side to MOVEP bytes in a loop, one at a time, in or out and not potentially lose them. That is to use the internal buffer that the ft245 chips do, so on the modern PC side I could use the driver and read the same byte stream sent by the 68k or write a stream of bytes and have it delivered to the 68k side.
Thanks.