exxos IDE interface (untested)

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Icky
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Re: exxos IDE interface (untested)

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Still shifting the board around, swapping some components around to reduce costs etc. Latest photo shows that the design is a lot smaller than the original DEV board.

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Re: exxos IDE interface (untested)

Post by exxos »

:bravo: This will now miss my MMU 4MB kit should it be fitted along with this IDE board :)

Will try and remember to order the ATF chips from mouser tomorrow!
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Re: exxos IDE interface (untested)

Post by PhilC »

Are we still testing the current version or waiting for the next?
If it ain't broke, test it to Destruction.
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Re: exxos IDE interface (untested)

Post by exxos »

PhilC wrote: Mon Mar 25, 2019 4:06 pm Are we still testing the current version or waiting for the next?
This one will be in my store once I get the PLD's from mouser.. There will be 6 PCB's and PLD's, no more of that design will be produced.

https://www.exxoshost.co.uk/forum/viewt ... =80#p18457

The V2 Icky is doing is all SMT.. So I can't program the chips without soldering them on... So the V1 I will program the chips which will get shipped with the PCB's.

V2 will be a long way off as its a new design , but is still based on V1s logic & code, Just more compact and with the currently untested byte swap function.
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Re: exxos IDE interface (untested)

Post by PhilC »

Ok, fair enough, so whatever we manage to break you can still implement on V2
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Re: exxos IDE interface (untested)

Post by exxos »

PhilC wrote: Mon Mar 25, 2019 4:26 pm Ok, fair enough, so whatever we manage to break you can still implement on V2
Exactly!
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Re: exxos IDE interface (untested)

Post by exxos »

Okay so these MOSFETS were definitely not the ones for this circuit... I had to use 3 diodes in series because the gate threshold voltage of the MOSFET is too low.. So I had to drop the voltage with the diodes..

Basically this circuit works..

When the wire is connected to 0V, the yellow LED lights (this is as per normal drive operation). When the wire is connected to 5V.. The yellow LED turns off, and the green LED turns on (of course this is dim because of the voltage drop across the diodes). When the wire is neither connected to 0V or 5V both LEDs are off.

So basically this is a successful test run.. I just need to find a MOSFET which has a higher gate threshold voltage.. I did find one ages ago that had 4V.. But I will have to look through them all again to find out which one it was :roll:


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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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Re: exxos IDE interface (untested)

Post by Icky »

exxos wrote: Thu Apr 11, 2019 4:48 pm Okay so these MOSFETS were definitely not the ones for this circuit... I had to use 3 diodes in series because the gate threshold voltage of the MOSFET is too low.. So I had to drop the voltage with the diodes..

Basically this circuit works..
Good progress exxos. Happy MOSFET hunting :). Will be a nice feature for the IDE board.
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Re: exxos IDE interface (untested)

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Icky wrote: Thu Apr 11, 2019 6:49 pm Good progress exxos. Happy MOSFET hunting :). Will be a nice feature for the IDE board.
Been looking in Farnell for like two hours now :roll: The only one I can find is: NDD02N60Z Which has a 3.0V Threshold with 4V being typical. What seems to be the theme is high-voltage MOSFETs. So smaller SMT devices like SOT– 23 are pretty much ruled out :(

The problem is a lot of MOSFETs have a threshold voltage of about 2V which is too low to ensure LED will turn off :roll: The one I am wanting has very specific tolerances in order for this circuit to work.. So this is no simple job by far. Going to places like mouser who have a wider range of parts may bring better look, but I wanted something to try tomorrow :)

If anyone really is bored enough to look through MOSFETs and please do so.. It would have to be a low-cost , small package, N channel, with a threshold voltage of at least 3V minimum.

EDIT:

Interesting is the BSS127 As at 5V it has 80R ON resistance..Which is pretty huge, though if I could actually find one around 200R, then it probably would not even need the current limiting resistor on the LED...hmmm...
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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Re: exxos IDE interface (untested)

Post by exxos »

Parts just arrived :)

Somehow think this is a bit of a overkill..

IMG_3975.JPG
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And the new video...




I don't think the green is as bright as the yellow though.. I changed from 220R to 68R, and while the brightness did increase, it was not really buying much.. It is still fine overall though.. If anything you may need to increase the resistor on the yellow LED as it is rather bright anyway..

So basically we now have a totally successful Alpha test :)

I love it when a plan comes together :thumbup:
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
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