On Tue, 16 Sep 2008 20:17:36 +0200, Peter Stuge peter@stuge.se wrote:
Joseph Smith wrote:
Joe, I remember you were interested in crazy hardware hacks. Would designing a floppy->parallel port interface (or floppy->serial) fit your bill?
That would be a crazy hardware hack. I don't think it would be too dificult considering floppies are basicly serial devices. I'll do some research.
These are the signals:
http://hardwarebook.info/Internal_Diskdrive
I think the hardest part would be a driver/software able to manipulate the floppy port for serial.
Not so hard, it will just be bit-banging the signals. I would suggest using 8 output signals, one strobe out and one ack in to increase the transfer rate.
The drawbacks are that timing and thus transfer speed will differ with CPU speed and that it is relatively impractical to drive communication like this.
I'd like to also nominate PS/2 for consideration, it already comes with a serial transceiver (odd-8-1) and once the superio is configured, writing one byte should need just a few io instructions.
http://hardwarebook.info/Keyboard_%286_PC%2C_PS/2%29 http://hardwarebook.info/AT_Keyboard/Mouse_protocol and the PORTS file from http://www.cs.cmu.edu/~ralf/files.html (search for K-P0060)
10-16.7 kHz it's kind of slow, but..
My vote is for PS/2 also. There's a data and a clk line, so simple. The question is, newer motherboards are not coming with PS/2 ports, only USB (especially BTX). So Carl-Daniel how many of those boards have PS/2? Here is my favorite site to find out what devices have what signals (and pin outs): http://pinouts.ru/
-- Thanks, Joseph Smith Set-Top-Linux www.settoplinux.org
In theory you could do the console out of SMBus, connect some PIC microcessor with serial port to SMBus on the host. You can always have special dimm module just with SDA and SCL.
This would just require additional hardware module. I think not so complicated.
Rudolf
Rudolf Marek wrote:
In theory you could do the console out of SMBus, special dimm module just with SDA and SCL.
This would just require additional hardware module. I think not so complicated.
The bug with all these ideas is that the superio has to be up. :\
(SMBus may be somewhere else, but it isn't always active from poweron.)
//Peter
The bug with all these ideas is that the superio has to be up. :\
Hmm. Correct me if I'm wrong but the superio has to come up for normal serial console doesn't it?
On 16.09.2008 21:10, Joseph Smith wrote:
On Tue, 16 Sep 2008 20:17:36 +0200, Peter Stuge peter@stuge.se wrote:
Joseph Smith wrote:
Joe, I remember you were interested in crazy hardware hacks. Would designing a floppy->parallel port interface (or floppy->serial) fit your bill?
That would be a crazy hardware hack. I don't think it would be too dificult considering floppies are basicly serial devices. I'll do some research.
These are the signals:
http://hardwarebook.info/Internal_Diskdrive
I think the hardest part would be a driver/software able to manipulate the floppy port for serial.
Not so hard, it will just be bit-banging the signals. I would suggest using 8 output signals, one strobe out and one ack in to increase the transfer rate.
The drawbacks are that timing and thus transfer speed will differ with CPU speed and that it is relatively impractical to drive communication like this.
I'd like to also nominate PS/2 for consideration, it already comes with a serial transceiver (odd-8-1) and once the superio is configured, writing one byte should need just a few io instructions.
http://hardwarebook.info/Keyboard_%286_PC%2C_PS/2%29 http://hardwarebook.info/AT_Keyboard/Mouse_protocol and the PORTS file from http://www.cs.cmu.edu/~ralf/files.html (search for K-P0060)
10-16.7 kHz it's kind of slow, but..
My vote is for PS/2 also. There's a data and a clk line, so simple. The question is, newer motherboards are not coming with PS/2 ports, only USB (especially BTX). So Carl-Daniel how many of those boards have PS/2? Here is my favorite site to find out what devices have what signals (and pin outs): http://pinouts.ru/
All of them have PS/2. However, some only have one PS/2 port which is either a pure keyboard or a combined keyboard/mouse connector. The latter may pose challenges regarding pinouts and/or electrical interfaces (multiplexing?).
Guys, have you noticed how similar this idea is to the often-derided USB flash key plugged into a USB<->PS/2 converter? That's a great thing! It means we'll attract all sorts of crazy hardware hackers.
Regards, Carl-Daniel
Guys, have you noticed how similar this idea is to the often-derided USB flash key plugged into a USB<->PS/2 converter? That's a great thing! It means we'll attract all sorts of crazy hardware hackers.
I've never heard of anyone doing that? I'd be curious if you have any links?
On 17.09.2008 00:34, Joseph Smith wrote:
Guys, have you noticed how similar this idea is to the often-derided USB flash key plugged into a USB<->PS/2 converter? That's a great thing! It means we'll attract all sorts of crazy hardware hackers.
I've never heard of anyone doing that? I'd be curious if you have any links?
Short version: Some keyboards are dual USB+PS/2 keyboards and have an USB connector by default. They often come with a pure passive adapter which will convert the USB pinout to a PS/2 pinout. http://us.st12.yimg.com/us.st.yimg.com/I/directron_2019_60686738 is an example image of such a female USB -> male PS/2 adapter. Of course, this will only work with devices supporting the PS/2 protocol natively.
Some time ago, a few pranksters (myself included) suggested to use such an adapter to plug USB flash drives into legacy PCs without USB ports. Of course that wouldn't work due to the passive nature of the adapter (electrical and protocol mismatch).
The PS/2 port is generally seen as a pure input "device" and using it for complex output (i.e. not just switching keyboard lights) will certainly baffle lots of people and confuse those "of course that won't work" experts.
Regards, Carl-Daniel
Carl-Daniel Hailfinger wrote:
All of them have PS/2. However, some only have one PS/2 port which is either a pure keyboard or a combined keyboard/mouse connector. The latter may pose challenges regarding pinouts and/or electrical interfaces (multiplexing?).
PS/2 uses four signals; power, ground, clock and data. Dual-purpose mini-DINs (e.g. page 10 in http://www.pcengines.ch/schema/alix1c.pdf) use the two last pins in a 6-pin connector for the second clock and data pair.
Y-cables are simple splitters.
The 6-pin connector is backwards compatible with 4-pin plugs, so plugging a keyboard directly into it will work without a splitter.
Carl-Daniel Hailfinger wrote:
Short version: Some keyboards are dual USB+PS/2 keyboards and have an USB connector by default. They often come with a pure passive adapter which will convert the USB pinout to a PS/2 pinout. http://us.st12.yimg.com/us.st.yimg.com/I/directron_2019_60686738 is an example image of such a female USB -> male PS/2 adapter.
The image shows a mouse adapter.
Did you actually take one apart to verify that it is nothing more than a passive adapter?
As you know, USB signals are much faster than PS/2, and I would be very surprised to see electronics in keyboards clever enough to support both over the same wires. That's not a simple trick.
I would however not be at all surprised to learn that those green and purple adapters actually have electronics in them to translate between USB and PS/2.
Some time ago, a few pranksters (myself included) suggested to use such an adapter to plug USB flash drives into legacy PCs without USB ports. Of course that wouldn't work due to the passive nature of the adapter (electrical and protocol mismatch).
I would instead guess that it will not work because the electronics in the adapter was designed and implemented to support one specific type of USB HID device. (Keyboard, or mouse, but not both. Oh, and if it was a passive adapter there would be no difference between keyboard and mouse adapters.)
The PS/2 port is generally seen as a pure input "device" and using it for complex output (i.e. not just switching keyboard lights) will certainly baffle lots of people and confuse those "of course that won't work" experts.
Those experts might be well served by reading up on the PS/2 protocol. The signalling is very much bidirectional between the keyboard controller on the mainboard, and the microcontroller in the actual keyboard itself.
//Peter
On 17.09.2008 02:06, Peter Stuge wrote:
Carl-Daniel Hailfinger wrote:
All of them have PS/2. However, some only have one PS/2 port which is either a pure keyboard or a combined keyboard/mouse connector. The latter may pose challenges regarding pinouts and/or electrical interfaces (multiplexing?).
PS/2 uses four signals; power, ground, clock and data. Dual-purpose mini-DINs (e.g. page 10 in http://www.pcengines.ch/schema/alix1c.pdf) use the two last pins in a 6-pin connector for the second clock and data pair.
Y-cables are simple splitters.
The 6-pin connector is backwards compatible with 4-pin plugs, so plugging a keyboard directly into it will work without a splitter.
Thanks for the info.
Carl-Daniel Hailfinger wrote:
Short version: Some keyboards are dual USB+PS/2 keyboards and have an USB connector by default. They often come with a pure passive adapter which will convert the USB pinout to a PS/2 pinout. http://us.st12.yimg.com/us.st.yimg.com/I/directron_2019_60686738 is an example image of such a female USB -> male PS/2 adapter.
The image shows a mouse adapter.
Did you actually take one apart to verify that it is nothing more than a passive adapter?
No.
As you know, USB signals are much faster than PS/2, and I would be very surprised to see electronics in keyboards clever enough to support both over the same wires. That's not a simple trick.
I would however not be at all surprised to learn that those green and purple adapters actually have electronics in them to translate between USB and PS/2.
Would checking connectivity with a multimeter suffice?
Some time ago, a few pranksters (myself included) suggested to use such an adapter to plug USB flash drives into legacy PCs without USB ports. Of course that wouldn't work due to the passive nature of the adapter (electrical and protocol mismatch).
I would instead guess that it will not work because the electronics in the adapter was designed and implemented to support one specific type of USB HID device. (Keyboard, or mouse, but not both. Oh, and if it was a passive adapter there would be no difference between keyboard and mouse adapters.)
One of the adapters in my collection supports keyboard and mouse (tested). I didn't check the others (they all look the same).
The PS/2 port is generally seen as a pure input "device" and using it for complex output (i.e. not just switching keyboard lights) will certainly baffle lots of people and confuse those "of course that won't work" experts.
Those experts might be well served by reading up on the PS/2 protocol. The signalling is very much bidirectional between the keyboard controller on the mainboard, and the microcontroller in the actual keyboard itself.
True.
Regards, Carl-Daniel
Carl-Daniel Hailfinger wrote:
I would however not be at all surprised to learn that those green and purple adapters actually have electronics in them to translate between USB and PS/2.
Would checking connectivity with a multimeter suffice?
Yep. I'm curious about the result!
One of the adapters in my collection supports keyboard and mouse (tested). I didn't check the others (they all look the same).
Cool! It's certainly possible to support both types of HID devices.
//Peter
On Wed, 17 Sep 2008 01:24:29 +0200, Carl-Daniel Hailfinger c-d.hailfinger.devel.2006@gmx.net wrote:
On 17.09.2008 00:34, Joseph Smith wrote:
Guys, have you noticed how similar this idea is to the often-derided
USB
flash key plugged into a USB<->PS/2 converter? That's a great thing! It means we'll attract all sorts of crazy hardware hackers.
I've never heard of anyone doing that? I'd be curious if you have any links?
Short version: Some keyboards are dual USB+PS/2 keyboards and have an USB connector by default. They often come with a pure passive adapter which will convert the USB pinout to a PS/2 pinout. http://us.st12.yimg.com/us.st.yimg.com/I/directron_2019_60686738 is an example image of such a female USB -> male PS/2 adapter. Of course, this will only work with devices supporting the PS/2 protocol natively.
Right.
Some time ago, a few pranksters (myself included) suggested to use such an adapter to plug USB flash drives into legacy PCs without USB ports. Of course that wouldn't work due to the passive nature of the adapter (electrical and protocol mismatch).
Carl-Daniel you prankster :-) Suprised if the fool that tried it didn't brick their flash drive. I thought you meant some hardware hacker had actually acomplished this. Now that would be sight to see :-)
The PS/2 port is generally seen as a pure input "device" and using it for complex output (i.e. not just switching keyboard lights) will certainly baffle lots of people and confuse those "of course that won't work" experts.
Agreed. Now we just need to figure out what kind of hardware to convert the DATA & CLK lines to serial.
Joseph Smith wrote:
Now we just need to figure out what kind of hardware to convert the DATA & CLK lines to serial.
They just need to be retransmitted at a different baud rate.
It could certainly be done with a single PICmicro or other small microcontroller. I suggest bitbanging the sync (PS/2) side because it is slower, and using a built-in UART peripheral for the RS-232 side.
The smallest PICmicro with UART is PIC16F688. It can run at 2MIPS with no external components. The PIC, a MAX232 and the caps needed could easily fit in a DB9 shell if a clever PCB design is created. (Double sided, mounted on the DB9 connector itself, PIC on one side, MAX232 on the other.)
A perfect little microcontroller project! :)
//Peter
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Carl-Daniel Hailfinger -
Joseph Smith -
Peter Stuge -
Rudolf Marek