Mottek: 2004-03-16

Serial Drivers

Now some background information about making the Air2Net card work with Blunt... The card uses a 16950 serial chip, which is in the default configuration compatible to the good old 16450 chip. The problem is however that this also means that the transfer buffers are only one byte "deep." This causes immediate overrun errors as soon as a bit more traffic is going over the wires. Fortunately, the '950 is simple to switch into other modes ('550, '650 and '750), so all that was necessary was to use the TSerialChip16450 class to talk to the chip and set some registers. The result is a new simple helper class which will from now on contain the chipset specific parts of Blunt.

On a related note, Daniel Padilla has gotten his hands on a Conceptronic CF card. Unfortunately, connecting to that card crashes the Newton. It too uses a 16950 chip, but it seems that it advertises its I/O space in a way that confuses the Newton, resulting in a crash when the registers are accessed. It would probably be possible to hardwire the correct parameters, but Daniel wants to take the card apart and use the internal module directly, similar to my setup.