I had run into those bits on the web and also a ps2 driver for the
arduino on github.
The protocols are similar for the PS2 mouse and the DEC mouse, 3 bytes
encoded with movement data.
Generic PS/2 Mouse Packet Bits
BYTE 7 6 5 4 3 2 1 0
0 yo xo ys xs ao bm br bl
1 xm
2 ym
Code Description
yo Y-Axis Overflow
xo X-Axis Overflow
ys Y-Axis Sign Bit (9-Bit Y-Axis Relative Offset)
xs X-Axis Sign Bit (9-Bit X-Axis Relative Offset)
ao Always One
bm Button Middle (Normally Off = 0)
br Button Right (Normally Off = 0)
bl Button Left (Normally Off = 0)
xm X-Axis Movement Value
ym Y-Axis Movement Value
DEC mouse bits (4800 Baud RS232)
BYTE 7 6 5 4 3 2 1 0
0 1 0 0 sx sy l m r
1 xm
2 ym
Code Description
sy Y-Axis Sign Bit
sx X-Axis Sign Bit
ao Always One
l,m,r Left, Middle, Right button
xm X-Axis Movement Value
ym Y-Axis Movement Value
This level of similarity made me think that a simple controller like the
arduino could easily handle this.
Doug
On 5/4/2018 3:13 AM, mark--- via cctalk wrote:
The Linux Kernel has support for DEC VSXXX mouse (as well as LK keyboards), the
opposite of what you are interested in.
So the conversion from DEC protocol is well documented.
It would be fairly straightforward with a microcontroller to implement the
reverse.
See: https://code.woboq.org/linux/linux/drivers/input/mouse/vsxxxaa.c.html
The major issue implementing support for DEC mice under Linux is the
requirement for a -12v power rail - clearly this isn't an issue with a modern
day replacement (I suspect it is a red-herring anyway for standard mice, just
because-12v exists at the DEC connector doesn't mean it is used, possibly it
was for digitizers for example).
The DEC mouse protocol is described here:
http://oldcomputers.dyndns.org/public/pub/rechner/dec/manuals/decimages/104aatm1.pdf,
section C6 onwards.
Regards, Mark.
-----Original Message-----
From: cctalk <[email protected]> On Behalf Of Bill Degnan via cctalk
Sent: Friday, May 4, 2018 3:06 AM
To: Douglas Taylor <[email protected]>; General Discussion: On-Topic and
Off-Topic Posts <[email protected]>
Subject: Re: DEC Mouse replacement
On Thu, May 3, 2018, 9:38 PM Douglas Taylor via cctalk < [email protected]>
wrote:
I would like to have a couple more DEC Mice for some Vaxestations I
have, but they seem to be pretty rare. At present I only have one
mouse and I move it from machine to machine.
The protocols for the DEC mice and the standard PS/2 mice don't seem
to be that much different.
Is it possible to use an arduino to translate PS/2 mouse output and
then send it to the vaxstation so that will it mimic a classic DEC mouse?
The jack is different, that would be a factor too.
B
