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Re: Enhanced parallel port for Apple 2?
Yves McDonald wrote:
In the PC world, the parallel printer port features bidirectionnal data
transfer with DMA capability. This feature was introduced around 1995
and was used to connect webcams, scanners, ZIP drives, etc. but I've
never heard about LAN adapters. The BIOS setup names for that feature
are ECP and EPP modes. Can't remember what that mean. On the Apple 2
side, the parallel port is strictly unidirectionnal (ex: good
ol'Grappler card). On the 2gs, there's no such thing as a parallel
port! To use parallel port adapters on an Apple 2, one should first
design a true parallel port card. This could be simple as wiring up an
interface chip such as the 6522 VIA chip (pretty old technology isn't
it?) and some 'glue' logic to the Apple bus.
The tough part is finding the byte command/data format to initialise the
LAN adapter. I have found a little bit of info on parallel port
adapters at the following address:
About 5 years ago an engineer showed what he considered a "failed
project" at an Apple II meeting. He said he'd found a couple of Apple II
parrallel printer cards that could be used bi-directionally. He had it
connected to a PC which he used as a file server. He said he considered
it a failure because the Apple II wasn't able to boot off the parrallel
card. The two cards he mentioned were the ProGrappler and the Macrotech
cards. I recall he had to run a program he wrote on the PC to use it as
a file server. I don't recall any more as I really didn't have any use
for the project.
Wayne