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Tempest

PS/2 Keyboard Interface?

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10 hours ago, Shift838 said:

Be aware for the TI you will still have to connect the board to a +5v and Ground source on the TI Power supply in order to prove the required voltage to the adapter.  so there will be 2 wires that have to be soldered to the PCB of the internal power supply.  They are on pretty big pads, so it is fairly easy to do.

The power supply is on a plug, why not just use a passthrough power cord? There's no need for any soldering if you can source the cables. This was my proof, though you can see I had to build cables. But if you're going to build a new PCB anyway, add the headers! ;)

 

CIMG1210.thumb.JPG.d0a847b54c681e20438fb8be62fa867a.JPG

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18 hours ago, Tempest said:

That would be an instant buy for me.  Any chance you could design it to be able to still use the original keyboard?

So working off JediMatt's design, I have come up with this.  The only 2 wires that will need to be soldered will connect to the 5v and GND connections.  I even added a extra 5v and GND tap to be used later if needed.

 

My plan is to get a few of these made on my next PCB order, should be soon.  Then just use a couple of pin header ribbon cables (15 position) to connect one (female to female) to the TI-99/4A PCB and the other (male to female) to the actual 99/4A keyboard.

 

I'm going to test with a different Teensy Microcontroller (Teensy LC) as the pinout is exactly the same has a Teensy 3.1/3.2 and it's a little bit cheaper(about $5 less).

 

 

2021-03-09_13-42-22.png

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10 hours ago, Tursi said:

The power supply is on a plug, why not just use a passthrough power cord? There's no need for any soldering if you can source the cables. This was my proof, though you can see I had to build cables. But if you're going to build a new PCB anyway, add the headers! ;)

 

 

True.  I need to find out which connector it is as far as molex type, etc..

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Posted (edited)
14 hours ago, Tursi said:

The power supply is on a plug, why not just use a passthrough power cord? There's no need for any soldering if you can source the cables. This was my proof, though you can see I had to build cables. But if you're going to build a new PCB anyway, add the headers! ;)

 

 

 

Do you happen to know the part number for the power connector is that plugs into the internal power supply?

Edited by Shift838

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6 hours ago, Shift838 said:

Do you happen to know the part number for the power connector is that plugs into the internal power supply?

Offhand, no, it's been over a decade since I built that, and I don't have a BOM (I did a quick search). IIRC it's .125" centers, shouldn't be too hard to find one that works?

 

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19 hours ago, Shift838 said:

So working off JediMatt's design, I have come up with this.  The only 2 wires that will need to be soldered will connect to the 5v and GND connections.  I even added a extra 5v and GND tap to be used later if needed.

 

My plan is to get a few of these made on my next PCB order, should be soon.  Then just use a couple of pin header ribbon cables (15 position) to connect one (female to female) to the TI-99/4A PCB and the other (male to female) to the actual 99/4A keyboard.

 

I'm going to test with a different Teensy Microcontroller (Teensy LC) as the pinout is exactly the same has a Teensy 3.1/3.2 and it's a little bit cheaper(about $5 less).

 

 

2021-03-09_13-42-22.png

To use the Teensy LC you will have to add level converters. The Teensy LC GPIO is NOT 5v safe.

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1 hour ago, jedimatt42 said:

To use the Teensy LC you will have to add level converters. The Teensy LC GPIO is NOT 5v safe.

good to know.  ill just stick with the Teensy 3.2

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i just soldered a bit of snap off header pins to the 5v and gnd on the power supply and use dupont connectors to connect the keyboard interface board's power ..easy  and removable

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If there was a USB connector that didn't require soldering, it would be awesome. Something like a plug and go.

I'm letting my imagination run wild again...

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4 hours ago, AtariNostalgia said:

If there was a USB connector that didn't require soldering, it would be awesome. Something like a plug and go.

I'm letting my imagination run wild again...

for what? power? seems overkill.. considering you have pins on the usb/ps2 board for power..  

 

If you mean for the keyboard interface, the interface is again.. pins.. no logic.  

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Posted (edited)
On 3/10/2021 at 3:17 AM, Tursi said:

Offhand, no, it's been over a decade since I built that, and I don't have a BOM (I did a quick search). IIRC it's .125" centers, shouldn't be too hard to find one that works?

 


I searched online through a lot of locking headers.

 

In the end, I found a match in JST VH series, 3.96mm pitch, which I have in the DirtyPCBs.com cable sample pack! Should have started with my parts bin.

 

You can order a finished cable online, here: https://dirtypcbs.com/store/cables

 

The PCB header is listed as BxxP-VH(-FB-B)  It has a triangle ramp on the outside.

 

Hmm, the cable is pricey. 20cm, Minimum order 100 pieces , $244 with shipping.

Edited by FarmerPotato
add price
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5 hours ago, FarmerPotato said:


I searched online through a lot of locking headers.

 

In the end, I found a match in JST VH series, 3.96mm pitch, which I have in the DirtyPCBs.com cable sample pack! Should have started with my parts bin.

 

You can order a finished cable online, here: https://dirtypcbs.com/store/cables

 

The PCB header is listed as BxxP-VH(-FB-B)  It has a triangle ramp on the outside.

 

Hmm, the cable is pricey. 20cm, Minimum order 100 pieces , $244 with shipping.

I can make the cables as long as I know what connectors they are..  😀

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I bought some of these MOLEX connectors a few years ago on eBay. Both halves show up there on occasion, but I had to hunt though a whole lot of listings until I found them. I used them up a long time ago. . .so I should probably go looking again.

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2 hours ago, Ksarul said:

Here are the right connectors on Amazon. . .the ones I found on eBay are cheaper, though. Note, these are the ones that go to the older style power supply boards. . .

Hmm, that is not the one in the console I opened today (beige).


I didn’t find the power supplies documented on the usual sites (Thierry, mainbyte) So you’ve got that connector type on a 4A ?


 

Molex is a brand name, they make thousands of parts.
 

Because of the floppy/hard drive power connector, the name turned into a commonplace, even though most of the “Molex” power plugs you see on ATX power supplies are Amphenol work alikes, Mate-N-Lock, not even Molex!

 

Here’s some of that series

 

https://www.mouser.com/Search/Refine?Ntk=P_MarCom&Ntt=169178262

 

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9 hours ago, FarmerPotato said:

Hmm, that is not the one in the console I opened today (beige).


I didn’t find the power supplies documented on the usual sites (Thierry, mainbyte) So you’ve got that connector type on a 4A ?

 

 

This style was in the power supplies for the /4 and the early /4A machines. The connector wasn't directly attached to the P/S board either--it was on a short cable. About 90% of all power supplies out there use the later 4-pin type that connects directly to the board.

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i'm waiting to get a protoboard back before I attempt to make a small run of these.  I should have it hopefully next week for me to test.

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Great!  Looking forward to hearing how it goes.

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Posted (edited)

still waiting on the test boards.  Here is a render of what I ordered.  No soldering required!  PS connector connects directly to the internal power supply board and the MB connector to the 99/4A motherboard.  Utilizes a Teensy 3.1 or 3.2 and a UHS Mini USB Host.  Based on @jedimatt42 design schematic.

 

Hoping to see the test boards soon.

 

 

v2.png

Edited by Shift838
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Nice!  Of course I have to figure out how to cut a hole for the USB port in the case.

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9 minutes ago, Tempest said:

Nice!  Of course I have to figure out how to cut a hole for the USB port in the case.

no hard.  on the 99/4a there are vents in the back.  I used as Jedimatt42 suggest using some good 3M double sided tape to stick it to the top of the case inside.  lined it up with a few of the vents and was able to snip the vents nice and neat.

 

 

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1 minute ago, Shift838 said:

no hard.  on the 99/4a there are vents in the back.  I used as Jedimatt42 suggest using some good 3M double sided tape to stick it to the top of the case inside.  lined it up with a few of the vents and was able to snip the vents nice and neat.

 

 

Oh great.  I'll try that then.

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Any updates?  I keep forgetting about this.

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