On 03/05/2012 11:10 PM, Gábor Lénárt wrote: > Hi, > > I prefer user port, because it exists on other machines as well, not just > C64. Like Plus/4. And it's my another question: it's not so clear for me: > has the Plus/4 some similar handshaking possibilities via its user port as > the C64/CIA has? No. The Plus/4 user port is completly different. The I/O-Bits are the portbits of a 6529B, one of them used to detect the button press for the datasette (If no tape is attached you have all 8 bits). Those are just I/O, no handshake other features available. You don't even have a data direction register. To use a bit as input, write a '1' to it before reading it. The Plus/4 also has a real ACIA (8551/6551A) for the RS232. You only need a few inverters and a MAX232 to be able to use it with a modem or a PC on the other side. Without modification, you can reach 19200 bps. This also means you cannot easily 'abuse' those I/O bits for other purposes. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2012-03-06 17:00:29
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