How do I properly hook up external LEDs I/O board 5.6 XL?

guzzard
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How do I properly hook up external LEDs I/O board 5.6 XL?

Unread post by guzzard »

I have a couple of questions regarding connecting the LEDs externally. Hopefully someone here can give me some guidance.
I looked at github (io board 5.6 pdf) and in various forum posts etc but have trouble understanding how to properly hook up the LEDs.

On the I/O board v. 5.6 XL:

1. P5 jumper seem to control both on-board and external LEDs? PDF indicate they control only the on-board LEDs. When removed I get no voltage on external pins (except disk 0,7v?). Is there a way to turn off the on-board LEDs in the ini-file? I have not found any such option.

2. With P5 jumper connected when LEDs are OFF I get between 1,4v - 1,8v on the external pins, and when they are ON I get zero volt. This seems low as well as inverted? I was expecting 3,3v when LED is on and 0v when LED is off? Can anyone clue me in on what's going on here, and how to hook this up properly?
guzzard
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Re: How do I properly hook up external LEDs I/O board 5.6 XL?

Unread post by guzzard »

For anyone else wondering..

1. P5 jumper functions as expected when connecting LEDs as shown below.

2. Connected LEDs as shown below and this works fine for me. This is based on other user posted images and various forum posts. I don't know if there is any official guide or information about this? I have searched but have not been able to find any official guide or info on the external LEDs or external buttons.
External LEDs.png
External LEDs.png (221.91 KiB) Viewed 274 times
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legacypixels
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Re: How do I properly hook up external LEDs I/O board 5.6 XL?

Unread post by legacypixels »

The LED signals are active low. The LEDs are always powered, and "turned on" by providing the ground.
US based seller of MiSTer addon boards. Visit www.legacypixels.com/mister
guzzard
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Re: How do I properly hook up external LEDs I/O board 5.6 XL?

Unread post by guzzard »

legacypixels wrote: Sun Sep 27, 2020 7:16 pm The LED signals are active low. The LEDs are always powered, and "turned on" by providing the ground.
When LED is off both plus and minus are at 5 V, so the potential difference is 0 V, and then LED is activated by dropping the voltage on minus to around 1.7 V making the potential difference around 3,3 V.

If I understand correctly this is what you mean as well?
Geords
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Re: How do I properly hook up external LEDs I/O board 5.6 XL?

Unread post by Geords »

Hi, Guzzard.

Just wondering which pins you're measuring 1.7v between? Are you measuring the voltage between the 5v pin (pin 1?) and the led signal pins (2, 3 and 4)? Or are you measuring against pin six, which looks like it /might/ be ground on your board according to the schematics? Warning: I'm not very good at reading those. :-)

Apologies if the XL is different to the normal 5.6? https://github.com/MiSTer-devel/Hardwar ... rd_5.6.pdf
guzzard
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Re: How do I properly hook up external LEDs I/O board 5.6 XL?

Unread post by guzzard »

Geords wrote: Fri Oct 02, 2020 5:20 am Hi, Guzzard.

Just wondering which pins you're measuring 1.7v between? Are you measuring the voltage between the 5v pin (pin 1?) and the led signal pins (2, 3 and 4)? Or are you measuring against pin six, which looks like it /might/ be ground on your board according to the schematics? Warning: I'm not very good at reading those. :-)

Apologies if the XL is different to the normal 5.6? https://github.com/MiSTer-devel/Hardwar ... rd_5.6.pdf
Yes, it was between ground and pins 2,3,4.
Geords
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Re: How do I properly hook up external LEDs I/O board 5.6 XL?

Unread post by Geords »

Yeah that must be a thing with analog boards. Neil on RMC youtube channel was building a desktop mister in a checkmate case and mentioned what sounds like a similar undervolt with an analog io board's led pins.

Around 7m50s :)
https://youtu.be/JGXZgVLh02Y

So the led pins are 5v off and of 1.7v on? I guess that makes sense with the diag above.

The reason I ask is that I'm thinking off swapping out my digital io board for an analog one and wondered if my current hex inverter led set up would work. I'm not sure it will if the led pins are doing 5/1.7v. Nor 1.7/0v for that matter...

Good to know!
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