I have an Action Replay 4m Plus and I know you can backup your saves to PC. I also know that in order to do so you have to have an ISA PC Comm link. My problem is that my PC does not have an ISA slot so the PC Comm link would do me no good. So my question is, has anyone figured out how to use the printer port, LPT1, to get your game saves from the card? If not can anyone point me in a direction to some C/C++ tutorials on programming device interaction using a parallel port or something similar? I'm sure you people get asked this all the time, but I really want to backup my saves and I cannot find the Saturn floppy drive anywhere either. Thanks for any help!
Backup Saves from ARP?
- Thread starter Dragoon42
- Start date
The most important differences are:
1) The AR typically has pins 12-25 connected directly to ground, while one of those pins is an output on the PC parallel port. Outputs attempting to drive a direct ground or Vcc connection can easily sink or source harmful amounts of current.
2) A Comms Link port has an "acknowledge" input that is connected, among other places, directly to the gate control of its output latch. This allows the AR to perform instant bus turnaround (reversing the data transfer direction from PC->AR to AR->PC), and therefore the AR/comms protocol has no stage that allows the PC side to delay bus turnaround - the AR can turn around the bus at any time after the PC has signaled a valid PC->AR byte. Since this is performed with a direct control connection, even causing an interrupt and having the ISR set the port to input mode by connecting this output to the parallel port's /ACK line would still leave a window in which both devices could be attempting to drive the bus. As above, this could cause excessive amounts of current to flow in the connection.
Personally, I think the Free Wing interface is overkill for modern parallel ports (I'd prefer a simpler EPP-friendly interface), but it's well-tested, well-supported, works on new and old ports, and beats the crap out of paying to have a Comms Link card shipped from Hong Kong. 🙂
1) The AR typically has pins 12-25 connected directly to ground, while one of those pins is an output on the PC parallel port. Outputs attempting to drive a direct ground or Vcc connection can easily sink or source harmful amounts of current.
2) A Comms Link port has an "acknowledge" input that is connected, among other places, directly to the gate control of its output latch. This allows the AR to perform instant bus turnaround (reversing the data transfer direction from PC->AR to AR->PC), and therefore the AR/comms protocol has no stage that allows the PC side to delay bus turnaround - the AR can turn around the bus at any time after the PC has signaled a valid PC->AR byte. Since this is performed with a direct control connection, even causing an interrupt and having the ISR set the port to input mode by connecting this output to the parallel port's /ACK line would still leave a window in which both devices could be attempting to drive the bus. As above, this could cause excessive amounts of current to flow in the connection.
Personally, I think the Free Wing interface is overkill for modern parallel ports (I'd prefer a simpler EPP-friendly interface), but it's well-tested, well-supported, works on new and old ports, and beats the crap out of paying to have a Comms Link card shipped from Hong Kong. 🙂
