Replacing a poker's microcontroller

[dsjbirch]

Can it be done?

Has anyone done it?

I was thinking of replacing it with a teensy.

I know nothing about electronics. Any direction would be much appreciated.

[hoggy]

May I ask why? Did you want to make it programmable?

[Daemon Raccoon]

I too have considered replacing the controller if only to gain a seperate Esc key and a proper Right Alt key.

A teensy would require a new case due to the size of its PCB. It's certainly do-able, but I haven't heard nor seen it done.

[JBert]

Maybe to hack in some missing keys...

Programmability would be nice as well though.

[fossala]

Why don't you just buy the real deal and get a HHKB

[dsjbirch]

The idea is to make it programmable, also add keys to pretend being a mouse and maybe leds too. You know, keyboard essential stuff!

[hoggy]

If you get an teensy, you could build Soarer's adapter while you figure out the rest of the details.

You should be able to do a chunk of the remapping that way.

[Soarer]

Not sure if the Poker can work with PS/2? Even if it could, you wouldn't be able to remap the Fn key, or fill in any keys on the Fn layer that don't already send codes.

Electronically, there's no problem replacing the controller; the only problems are physical. First, the original controller needs to be disconnected, and this means destruction - either remove the chip or cut the tracks. Second, finding space for the Teensy and its USB cable (it would be easiest, I think, to make a new cable exit). Going by webwit's pics, it looks like there might just be enough space beneath the PCB at the rear of the case.

[JBert]

Not sure if the Poker can work with PS/2?

I checked that, it can work in PS/2 if you connect it through a passive adapter. There are some interesting solder pads on the PCB if you want to go this route, just open the circuit by desoldering 2 SMD resistors, then reuse the existing USB connector by soldering to 2 pads reserved for buffering capacitors.

The teensy should also fit in the case if it sits just beneath the PCB. You will need to cut some grooves in the ridges which give the case strength if the wires connecting the Teensy can't be squashed beneath the PCB.

[Soarer]

That could work pretty well then! The remaining challenge would be to see if the Fn key can be rewired to output a useful code for remapping (even if it then gets remapped to a Fn key in my converter!). That would need for there to be some unused position in the matrix that puts out a unique code, or to double it up with another key. That's still slightly destructive, but far less than removing the controller chip

[hasu]

I prefer new designed PCB for Poker like PrinsValium did for Filco on Phantom project at GeekHack. Maybe you should use ATMega32U4 directly instead of Teensy because of small space of PCB and its case.

It will be fun if you can define physical layout of switches and logical layout of programmable layer in your preference!

[dsjbirch]

Ok I've got a teensy. I'm thinking that my ideal solution would be to remove the current microcontroller and replace it with something with the same pin layout and surface mountable. Any suggestions?

[dsjbirch]

It seems the current controller is a holtek HT82K94E and it's the 48 SSOP-A (whatever that means).

http://www.holtek.com/english/docum/computer/82k94x.htm

EDIT: I've filled in the company contact form requesting information about getting started writing a custom firmware...

[Soarer]

That sounds like a difficult and expensive way to do it!

[Maarten]

How about trying to jam a Chameleon in there? If you remove some parts from the board you can get it down to under 3.5mm in thickness.. sure something that small could be mounted inside any case?

[dsjbirch]

How about trying to jam a Chameleon in there? If you remove some parts from the board you can get it down to under 3.5mm in thickness.. sure something that small could be mounted inside any case?

Looking at a teensy, there's not much to it either, the usb connector could be removed and perhaps the original could somehow be rewired to replace it?

I'll need to take a closer look.

Also need to consider how to add new leds to the switches and if a simple teensy (not a teensy++) has enough ports to make pretty patterns with the leds.

[dsjbirch]

Holtek passed me onto the UK distributor who basically said, try RS. MOQ is 1000. He didn't mention a price. I wonder is it possible to buy the chip programmer, de-solder the existing chip from a poker and re-program it?

[Maarten]

well... never say never but you always gotta ask yourself if its worth the trouble (especially if youre not a electronics nutcase). If i were you id keep it 'simple' at first and try a teensy or chameleon.

[JBert]

He didn't mention a price. I wonder is it possible to buy the chip programmer, de-solder the existing chip from a poker and re-program it?

I value your perseverance but do you know anything about electronics? The chip is a PROM as far as I know (i.e. one-time programmable). EPROM chips have a special window which allows them to be erased using UV light, but this one doesn't.

Seriously, don't let this stop you, connecting a Teensy++ might be perfectly doable. I know I haven't had the courage to do so yet.

[Maarten]

Wait... isnt the Holtek thing an MCU? Its got RAM and everything, shouldn't that mean that in theory it should be possible to re-flash it given the proper hardware?

[ripster]

My 87u has dip switch 4 for reprogramming the firmware.

Never used it though.

[Maarten]

My 87u has dip switch 4 for reprogramming the firmware.

Never used it though.

Does that have the same chip thingy as the Pokers?

[JBert]

Wait... isnt the Holtek thing an MCU? Its got RAM and everything, shouldn't that mean that in theory it should be possible to re-flash it given the proper hardware?

Sadly, there's a difference between RAM and Flash memory.

Check the ref sheet page for the controller (granted that it is the right one): http://www.holtek.com/english/docum/computer/82k94x.htm :

The mask version HT82K94A is fully pin and functionally compatible with the OTP version HT82K94E device.

OTP = One Time Programmeable, and a mask version means the manufacturer actually puts down the firmware during the chip's fabrication (mind you, I just read this last bit on Wikipedia: Mask ROM).

If you really want a customized Holtek controller, the Vortex guys might be more likely to help than Holtek themselves...

[ripster]

This would be a great feature for the Happy Hacking Professional 3.

My new Thermopen thermometer has DIP switches and I am not happy about it.

[dsjbirch]

I value your perseverance but do you know anything about electronics?

TLDR; In a word. No.

I took a semester at Uni once. Built an "alarm" system. Programmed a chip too.

[JBert]

I value your perseverance but do you know anything about electronics?

TLDR; In a word. No.

For the record, I didn't mean to offend with that statement.

[ripster]

I partially learned electronics building 500V guitar tube amplifiers so laugh at these solid state electronics voltages and especially AMPS!

And haven't looked at my Topre microcontoller pics. They are blocked right now until I get to my pc.
http://geekhack.org/showthread.php?3121 ... ffness-Mod

[dsjbirch]

I value your perseverance but do you know anything about electronics?

TLDR; In a word. No.

For the record, I didn't mean to offend with that statement.

Oh dude, noooooo problem!

I don't know anything about electronics, and I think it's totally fine to ask.

I did presume, that you _do_ know something about electronics though, because of the question.

I shall now take the opportunity to pose the question to the whole thread.

... Do you infact know electronics?

Those that answer yes, will probably face quizzing at some point in the future. When I break something! ... Hopefully, just before!