I want to be a tolerant host and pass them a keyboard that matches their faulty teachings, but the devil has many forms. I sometimes share my keyboard with the pitiful waifs who have never known the glory of the original home of the Ctrl key.
But there are some who cling to the old religion.Īlas and forsooth, there are but few left. A great many were led astray those that were not were washed away in the rising tide of ignorance. In their cunning, they did see that the programmers were much too busy hunting the wumpus to notice a switch, and they did stick the infernal Caps Lock key in the righeous place of the Ctrl key and began the Great Deception: they did claim that computers were now easy to use and thus we had no need of nerdist keys like the unwholesome Ctrl. They wanted Secretaries to buy PC's in their thousands. Thus, the Ctrl key it needed a place to go, and since we happened to have a convenient place with no particular mission, well, there it was.Īnd thus it was that the programmers were satisfied, but then the profiteers at IBM were not. We didn't need lowercase letters to play Zork, but we did need a way to signal to the computer that we had grander ambitions than just typing a letter. One does not need more than six bits to program in Fortran for at one time we knew that lowercase letters were the work of bourgeois capitalists. Oh and many do ask, "Did God really put the Ctrl key to the left of the A when he molded the first keyboard out of Adam's 14th rib?" Surely it was so. Why you ask? Because in addition to the wonder of clicky keys, with the 102 you can configure the Ctrl key to be to the left of the A, where God intended it to be. You see, while a Model M (what I have managed to get hold of at work) is good, the true pinnacle of keyboard perfection is what I have at home, the OmniKey 102. Facts are good, I'm not saying they're not, but I have pointless over-complication on my side, so I'm afraid you're outgunned. Well, now, what your bringing up here are facts. I'm pretty new to the Arduino, so I could be making a fundamental mistake. I could go low-tech and get a shift register to do the same.īut before I chase down those options, I thought I'd ask if anybody thinks I've misread things.
#Ps2 keyboard to usb converter adapter ps2
I could fix it: I could use another Arduino to handle the PS2 and present a buffered stream to the USB-facing Arduino.
It just looks to me like it's just not possible to have USB communications and any other microsecond-resolution real-time process going on in a single Arduino. Well, I say that like a bad thing, but, from what I understand of the V-USB implementation, it has to be like that. What makes matters worse is that the USB interrupt is relatively long - as it processes the entire message in a single interrupt event.
#Ps2 keyboard to usb converter adapter code
The USB code is fantastically timing-critical, and the PS2 is too - you have very few instructions after each clock tick interrupt to get the data line read or written. I believe what's going on is that while the USB is processing its interrupt it's skipping handling the PS2's interrupt. If I disable the USB send, I don't get any errors no matter how much I flog the keyboard.
Somewhere in all that flailing, I can get some kind of bit error that feels like dropped interrupts. I can reproduce the problem reliably just by mashing keys wildly for several seconds. That is, in a normal day of typing it makes about one mistake every 15 minutes. Even with the re-send requests, the adapter works almost all the time.
To "make it robust", I add start/stop and parity checking and added the ability to send NACK commands back to the keyboard to get it to re-send on error. The standard implementation is to have the clock tied to an interrupt, so you get an interrupt per bit. If you aren't familiar, the PS2 keyboard communicates with a data & clock pin, serially. I started with the V-USB library and some other PS2 keyboard library (which I basically rewrote in order to make it robust.) I've been puttering around with an Arduino, using it to adapt an IBM Model M keyboard to a USB port.
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