rb@cc.ic.ac.uk (Robin Becker) (07/07/90)
I have two PS/2's one is a model 80 (really low end 16Mhz.) and the other is a 20Mhz. model 70. When I run the telix comms package I get different behaviour when I exit from the package. On the model 80 telix can exit without hanging up, but on the model 70 it doesn't even ask if you want to hang up. It seems as though telix knows there's no point. All the same it seems to drop the line anyway. Any one out there got any ideas? Robin
frisk@rhi.hi.is (Fridrik Skulason) (07/10/90)
This is not a reply to the original posting, but I have noticed that the serial port on PS/2 70 machines is different from any other serial port I have been working with. I have been interfacing switches to PCs, as a part of a project to assist handicapped childern to communicate. This includes digital (not analog) joysticks, as well as sets of 1,2,5 or 8 switches. I can use the parallel port for the input of up to 8 bits, but thw serial port can only be used to input 5 bits. The problem is that with PS/2 70, using the serial port for input in this way simply does not work and I have no idea why. This is no problem, as the machines are far to expensive to be used in the project, but I still wonder why. So - does anyone know what makes the PS/2 sertial port different from other serial ports ? -frisk -- Fridrik Skulason University of Iceland | Technical Editor of the Virus Bulletin (UK) | Reserved for future expansion E-Mail: frisk@rhi.hi.is Fax: 354-1-28801 |
grege@gold.GVG.TEK.COM (Greg Ebert) (07/11/90)
The PS/2 uses a 16550, whereas the AT uses a 16450. The 16550 has internal transmit and receive FIFOs, which SHOULD be transparent to software, but judging by the piss-poor code out there (mislabled as software), I would not be surprised people are finding problems. Get the data sheet for the 16550.
doerschu@rex.cs.tulane.edu (Dave Doerschuk) (07/11/90)
In article <1151@gold.GVG.TEK.COM> grege@gold.GVG.TEK.COM (Greg Ebert) writes: >The PS/2 uses a 16550, whereas the AT uses a 16450. The 16550 has internal >transmit and receive FIFOs, which SHOULD be transparent to software, but >judging by the piss-poor code out there (mislabled as software), I would not >be surprised people are finding problems. Get the data sheet for the 16550. I couldn't agree more, there is a lot of staggeringly bad comm software out there! Chuck Forsberg (Owen Technology) in his DSZ zmodem implementation mentions that the only 16650 chips he recommends are: 1) NS16650AN 2) NS16650AFN Both these chips have a 16-deep receive FIFO; but the FIFO must be explicitly enabled by the communications software. That is, the default is to not use the FIFO buffer (this should be true for any 16650). Chuck specifically mentions Western Digital's WD16650 chip as having problems operating at speeds less than or equal to 2400 bps. You might want to crack open your box and look at the chip you've got. If its anything other than one of the two listed above, you may want to change it out. Dave doerschu@rex.cs.tulane.edu