FALCON CLOCK BUFFER PATCH NEW

Various tweaks and fixes from video ghosting to audio fixes etc.
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FALCON CLOCK BUFFER PATCH NEW

Post by exxos » Tue Aug 22, 2017 10:52 pm

buff1.jpg
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My buffer board replaces any other/older boards/hacks which may be in the Falcon already. There are so many "versions" of this mod its unreal. All of which are old outdated designs and should now be "forgotten" about. I designed this board in 2017 to clean the clock lines up and buffer them while reducing ringing in the signals. I have had nothing but good feedback about this mod resolving problems.

The problem with the Falcon is the source of the 16MHz clock came from a single source which wasn't really strong enough to drive everything which was connected to it. Atari split this clock line 3 ways and added some small resistors (which is a good idea). Though unfortunately, this resulted in "back ringing" on the signals where noise on one line would couple to noise from another. With such low resistor values and various lengths of tracks running all over the place, it basically turned into a mess. All buffer boards aim to buffer these 3 signals but in multiple ways, where some could actually make things worse!

Some (or most) buffer the signals with a small buffer IC. This is great, but the signals still had bad ringing and only "better" buffer mods aimed to reduce this, mostly C-lab and Steinberg etc. I had not heard of any Falcons having this mod, so not sure what the outcome was.

In anycase, I started with a buffer IC and added in resistors to reducing the ringing on the inputs and outputs of the clock lines. Each resistor was chosen for the best "compromise" between voltage levels and noise levels (both are conflicting requirements unfortunately) on each signal patch. This way all 3 clock lines are driven separately and have the buffer resistors to reduce the ringing which could cause "double clock pulses" and cause glitches in some parts of the Falcons DMA circuit.

These boards offer a low cost compact solution to solving the noise on the clock lines and have solved a lot of various issues people have been having.

MORE INFO
http://www.exxoshost.co.uk/atari/last/f ... m#EXXOSMOD

WEB STORE LINK
https://www.exxoshost.co.uk/atari/last/storenew/#0073

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4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

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Re: FALCON CLOCK BUFFER PATCH NEW

Post by exxos » Tue Nov 28, 2017 3:12 pm

A slightly better image of the install (plus my RTC module :) )

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4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

User avatar
exxos
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Re: FALCON CLOCK BUFFER PATCH NEW

Post by exxos » Fri Mar 15, 2019 11:34 am

I have done a revised design which should address the noise on the SDMA clock better. This mostly seems to rear its head with boosters such as the phantom etc. Though I do not own one so I am unable to test.

This design will replace my original clock patch design. I ordered the PCB's a couple weeks ago, and currently waiting for them to arrive. Once I have built up and tested them, they will be back in stock.


a9a33c36379dc5ded41086ff57ad3043.png
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4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

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