Re: Supporting a PS/2 Keyboard

Ok thanks. I guess putting in the 8042 part would mean interfacing it
to the CPU so it shows up at the proper standard I/O map for a
keyboard. Since you may have gone this route, I'd appreciate any info
you can point to here. I'm sure the hardware guy can figure it out but
it may help.

Paul G. Tobey [eMVP] wrote:
No, nothing that I've ever seen. It would not be portable, anyway, as the
GPIO functions for each processor version would be different. Even if you
found one that worked fine on Samsung processor, say, it wouldn't
necessarily work on a PXA processor.

Yes, I guess so. That seems rather more complicated than just putting an
8042 on the board, but it might work. I don't have any USB to PS2
converters around here or I'd try it on the Mainstone board. I guess that
you could do the same with whatever reference design hardware you have.

I don't know what the internals of the PS/2 to USB converters are, but it's
not just translating signal levels or something. USB devices have to
identify themselves among other behaviors.

Maybe it's just because I've done it this way, but adding an 8042-type
device, seems much simpler than hard-wiring a USB to PS/2 converter onto
your board...

Paul T.

"tvle" <tvle@xxxxxxxxxxx> wrote in message
news:1165423933.232177.276280@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Thanks. So there's not anything in Platform Builder that does a direct
interface to the PS/2 connector then, right? E.g. The NOP keyboard
driver doesn't help here then?

One alternative then is to get the hardware guy to put a PS/2 to USB
plug in the hardware and have that plug connected to the USB port of
the hardware board. I assume that CE's USB HID driver supports a USB
keyboard out of the box right? So there's not an additional driver
that needs to be included/loaded.

On the USB keyboard or the PS/2 to USB plug then there must be some
active component that does the function of the 8042 and does it through
the USB connection (?). I assume there can't be just a connection to
convert PS/2 signals to USB signals but obviously I'm not that familiar
with how that works. I want to make sure there's not some way of
interfacing directly to the PS2 connector through the supplied PB
code/drivers. I'd rather not try and implement the 8042's firmware in
my code if there's already something available...

Thanks again for your time in replying to my messages.

Paul G. Tobey [eMVP] wrote:
As I said, anything is possible, but you're going to have to figure out
the
timing and interpretation of all of the keyboard signals. You get to be
the
first, so you'd better get started ;-)

The USB keyboard driver is an HID driver. The keyboard part is just the
interpreter that converts the scan codes returned by the USB part of the
driver into characters (that is, it knows what scan code on the keyboard
corresponds to the "U" key and does the right thing to translate the scan
code into "U", when asked by the keyboard driver).

There are various keypad drivers in BSPs for development boards and, as I
said, there's the 8042 driver in source form in Platform Builder. You
won't
run out of examples. It's the hardware interfacing that's the hard part.

You can use an 8042 controller. Driver is written for you. Hardware
cost
goes up.

You can implement some sort of 8042 IP in an FPGA or CPLD. Driver is
written for you (although you have to be sure that the interface to the
"8042" really looks like an 8042). Hardware cost might go up, if you
have
to use a bigger FPGA/CPLD than you have on your board now, or, if you
have
free space in your programmable device, maybe not.

You can try to do everything from software with GPIO. You have to do
everything in software. Hardware cost is not affected.

Paul T.

"tvle" <tvle@xxxxxxxxxxx> wrote in message
news:1165361407.083282.288950@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Thanks for the reply.

We have a legacy UI device that we are trying to replace with a new
Intel PXA270 based board and Windows CE 5.0. The legacy device allowed
the user to plug in a PS/2 keyboard if they wanted to use it on some
screens that required alot of input. The UI device had no real
intelligence to it and basically sent info back to a host computer via
an RS232 serial link using a proprietary serial protocol.

The host computer received the message containing the key codes and
reacted accordingly (by sending subsequent data back to the UI device.

The replacement device with CE does not have an 8042 in the hardware
and the thought was that the PS/2 connector would be wired to the CPU
I/O pins and software would handle interfacing to the keyboard.

Is this possible? How does the USB driver for a USB keyboard work in
CE? Does it layer itself so that it eventually reuses the keybd driver
or associated dll's?

Or will the hardware need to be redesigned to have the 8042 controller
or have a PS2 to USB converter plug?

Thanks for any and all comments and suggestions here.
Paul G. Tobey [eMVP] wrote:
Anything is possible, but it seems like there would be a lot of little
gotchas that you'd have to implement in software running on the main
processor. You could just put an 8042 in there; there's a driver for
it
in
Platform Builder.

I don't understand what passing the codes from your device to the
serial
port has to do with how the keyboard codes are arriving. Am I missing
something? Are you saying that you need something at a different
level
than
what an application running on the device to which the keyboard was
connected would get?

Paul T.

"tvle" <tvle@xxxxxxxxxxx> wrote in message
news:1165357189.374073.223080@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi everyone,

Is it possible to have a PS/2 keyboard connector interfaced directly
to
the Intel PXA270 (via GPIO pins) and leverage the existing KeyBD
driver
to get scan codes from the keyboard? Obviously there's not an 8042
keyboard controller in the chain so I don't know if its possible to
do
this. We have an application which basically is supposed to grab
the
raw codes from the keyboard and passes them over a serial connection
to
another application.

I'd appreciate any comments or suggestions any of you may have on
this.

Thanks.




.

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