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  #1  
Old 07-28-2009, 08:13 PM
Geoff Harrison Geoff Harrison is offline
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Default 2SIO silkscreen error

If you're building one of Grant's 2SIO boards, be aware that the silkscreen is incorrect for D3, D6, D9, D12, D15 & D18. The cathode should be up toward the Molex connectors, instead of down as shown on the silkscreen.

This matters only if you are configuring the board for a current loop device, those diodes are not used if you are configuring it for RS232.

Geoff.
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Old 07-28-2009, 09:58 PM
TomL_12953 TomL_12953 is offline
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Originally Posted by Geoff Harrison View Post
If you're building one of Grant's 2SIO boards, be aware that the silkscreen is incorrect for D3, D6, D9, D12, D15 & D18. The cathode should be up toward the Molex connectors, instead of down as shown on the silkscreen.

This matters only if you are configuring the board for a current loop device, those diodes are not used if you are configuring it for RS232.

Geoff.
Does this mean my TTY would've worked???

Tom L
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Old 07-28-2009, 10:01 PM
marty marty is offline
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Talking silk screen

Hi Geoff;
THANK YOU THANK YOU for your excellent work , again...
Now if I could get my 2-sio to work with a mbl prom or a debug eprom, I would be happy if I could get my s-io (single port) to work with either...
THANK YOU Marty
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  #4  
Old 07-28-2009, 11:03 PM
Grant Stockly Grant Stockly is offline
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Default

I just confirmed that there was a mistake on the boards. The diodes are correct on the board scans, but when I was done processing the artwork they are flipped. I don't remember exactly how I processed the artwork...but I do know I used the same diode stamp fo all the positions. I must have flipped it for the bottom 8 diodes and not noticed for the top???

If I decide to make more 2SIO boards I will fix the problem. Thanks for finding that!

If you've sent me an e-mail in the last few days, I will try to answer it tonight. I changed the settings for "non unicode" programs to Korean and now most of my Eudora filters don't work. I'm slowly changing all of the filters to work and I should be able to get to the e-mails tonight. Right now there are a few good e-mails in a sea of mailing list subscriptions!
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  #5  
Old 07-28-2009, 11:19 PM
Geoff Harrison Geoff Harrison is offline
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Default

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Originally Posted by TomL_12953 View Post
Does this mean my TTY would've worked???

Tom L
Well, with the diodes installed as per the silkscreen, no input signals were getting through to the UART. After I rotated them, the input was getting through,

but...

the pulses arriving at the UART are very messy (see the scope trace below) and I'm not sure why. The UART can't handle it. I'll play with it a while longer, but I think it makes most sense to convert it to RS232. As you said elsewhere, it will make for a more versatile interface.




The bottom trace is the input to IC K pin 9, which is supposed to be more or less TTL, the top trace is the output from IC K pin 8, which should be a clean TTL square wave.

Geoff.
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Old 07-29-2009, 01:08 AM
TomL_12953 TomL_12953 is offline
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Default 2sio

Quote:
Originally Posted by Geoff Harrison View Post
The bottom trace is the input to IC K pin 9, which is supposed to be more or less TTL, the top trace is the output from IC K pin 8, which should be a clean TTL square wave.

Geoff.
So could IC K be bad?

Tom
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  #7  
Old 07-29-2009, 01:41 PM
Geoff Harrison Geoff Harrison is offline
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Default

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Originally Posted by TomL_12953 View Post
So could IC K be bad?

Tom
I changed it just to be sure, but that's not it. The problem is that the incoming data stream, after being converted from current loop to TTL voltage swings is not clean enough to drive the 7404 inverter properly. For all I know it may be a problem with the current loop/RS232 adapter I'm using to drive the board.

Did you verify that you can drive your asr33 with your adapter correctly? If so, then switching the 2SIO port to RS232 should get you up and running.

Geoff.
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Old 07-29-2009, 02:11 PM
TomL_12953 TomL_12953 is offline
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Originally Posted by Geoff Harrison View Post
Did you verify that you can drive your asr33 with your adapter correctly? If so, then switching the 2SIO port to RS232 should get you up and running.

Geoff.
Yes. I was running the TTY on port 2 with my converter sucessfully so if you could just change port 1 to RS-232 (still 110 baud of course!) I'd be all set.

Thanks!
Tom
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