On Monday 24 September 2001 23:02, you wrote:
> How many bytes could I send approximately in one interrupt by using a
> serial cable (com port on PC and joystick on MSX)?
Don't connect the COM port to anything other than RS232, because the COM port
signals are at 12V.
JoyNet can be used between a PC parallel port and an MSX joystick port. You
can find the schematics on Laurens' site. If you want a simple low-cost
cable, please use JoyNet. Its speed is good enough for multiplayer games or
telnet, but it's a bit slow for transferring files.
> Just by making a little program on MSX that keeps checking for data...
On an MSX2 I got about 3.5 kilobyte per second, on turbo R about 14 kilobyte
per second. (At the other side of the cable was the same PC in both cases.)
As you can see, the bottleneck is the CPU, not the cable. The joystick port
is not very convenient for I/O, because you have to switch PSG registers a
lot (between reg 14 and 15). Also, there is no buffering (RS232 has FIFOs and
you can send bytes to the interface instead of single bits).
Bye,
Maarten
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