Help with SX64 User Port?

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Help with SX64 User Port?

Leif Bloomquist
Hi all,

Some of you know I've been tinkering with an Arduino-based Wifi
"Modem" for the Commodore 64 etc.  (Pics here:
http://imgur.com/a/ZvwO6)

It's almost ready to go, however, one issue is that it doesn't work on
the SX64, and it's the same issue on at least two SX's.

The symptom is that while the Arduino receives serial data from the SX
fine, nothing sent by the Arduino is received by the SX.   I've also
tried going directly to the Wifi board (which is also serial), same
issue.   It works fine on a normal 64/64C though.

I'm aware that there are some differences with the SX User Port
compared to a normal 64/64C  (one of the 9VAC lines is "grounded",
from what I've read).  I don't have a lot of electronics background so
I could really use some help.

An EZ232 works just fine on my SX, so it's clearly possible.  This is
all at 2400 baud.

Some theories I have:

-I tied all the grounds (both signal and protective ground) on the
user port together on my board, could there be an issue from the 9VAC
coming through the ground?   (I'm not using the 9VAC pins themselves,
they aren't even connected.)

-I'm going through 330 ohm resistors to protect the CIA  (i.e. in case
User port and Arduino pins are both outputs).  Could this be putting
the TTL signal out of spec on the SX, but not on the 64(C)?

I'll post a schematic momentarily, but wanted to ask if anyone has
some advice or info as to what the problem might be?

Thanks
-Leif


--
Leif Bloomquist | [hidden email] | +1 416-737-2328 | Check out
my blog! http://www.jammingsignal.com

"Every choice, no matter how small, begins a new story." - xkcd

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Re: Help with SX64 User Port?

Daniel V. Mackey
At 09:09 PM 10/12/2015, you wrote:

>Hi all,
>
>Some of you know I've been tinkering with an Arduino-based Wifi
>"Modem" for the Commodore 64 etc.  (Pics here:
>http://imgur.com/a/ZvwO6)
>
>It's almost ready to go, however, one issue is that it doesn't work on
>the SX64, and it's the same issue on at least two SX's.
>
>The symptom is that while the Arduino receives serial data from the SX
>fine, nothing sent by the Arduino is received by the SX.   I've also
>tried going directly to the Wifi board (which is also serial), same
>issue.   It works fine on a normal 64/64C though.
>
>I'm aware that there are some differences with the SX User Port
>compared to a normal 64/64C  (one of the 9VAC lines is "grounded",
>from what I've read).  I don't have a lot of electronics background so
>I could really use some help.
>
>An EZ232 works just fine on my SX, so it's clearly possible.  This is
>all at 2400 baud.
>
>Some theories I have:
>
>-I tied all the grounds (both signal and protective ground) on the
>user port together on my board, could there be an issue from the 9VAC
>coming through the ground?   (I'm not using the 9VAC pins themselves,
>they aren't even connected.)
>
>-I'm going through 330 ohm resistors to protect the CIA  (i.e. in case
>User port and Arduino pins are both outputs).  Could this be putting
>the TTL signal out of spec on the SX, but not on the 64(C)?
>
>I'll post a schematic momentarily, but wanted to ask if anyone has
>some advice or info as to what the problem might be?
>
>Thanks
>-Leif


Hey Schema,
There is a MOD for the expansion port. I can't for the life of me
find the link at the moment, maybe someone else
can find it. I DID do the mod on my SX when I had it apart awhile back.


---
WWW: http://www.commodoredungeon.com

QUOTE : "A Clean bench is a sign of a weak mind."


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Re: Help with SX64 User Port?

Leif Bloomquist
In reply to this post by Leif Bloomquist
Following up on my earlier question about using this on an SX64,
here's the schematic: http://i.imgur.com/OVkLEMG.png

I'm open to other suggestions on the design as well (it's my first PCB
of any complexity)

Thanks,
-Leif


--
Leif Bloomquist | [hidden email] | +1 416-737-2328 | Check out
my blog! http://www.jammingsignal.com

"Every choice, no matter how small, begins a new story." - xkcd

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Re: Help with SX64 User Port?

Leif Bloomquist
In reply to this post by Daniel V. Mackey
Thanks, I know about the mod  (link is
http://project64.c64.org/hw/sxuserport.txt, I believe).

I'd hate to have to ask users to mod their SX, especially since an
EZ232 works on a stock SX64.

Cheers,
-Leif


On Mon, Oct 12, 2015 at 9:20 PM, Daniel V. Mackey <[hidden email]> wrote:

> At 09:09 PM 10/12/2015, you wrote:
>>
>> Hi all,
>>
>> Some of you know I've been tinkering with an Arduino-based Wifi
>> "Modem" for the Commodore 64 etc.  (Pics here:
>> http://imgur.com/a/ZvwO6)
>>
>> It's almost ready to go, however, one issue is that it doesn't work on
>> the SX64, and it's the same issue on at least two SX's.
>>
>> The symptom is that while the Arduino receives serial data from the SX
>> fine, nothing sent by the Arduino is received by the SX.   I've also
>> tried going directly to the Wifi board (which is also serial), same
>> issue.   It works fine on a normal 64/64C though.
>>
>> I'm aware that there are some differences with the SX User Port
>> compared to a normal 64/64C  (one of the 9VAC lines is "grounded",
>> from what I've read).  I don't have a lot of electronics background so
>> I could really use some help.
>>
>> An EZ232 works just fine on my SX, so it's clearly possible.  This is
>> all at 2400 baud.
>>
>> Some theories I have:
>>
>> -I tied all the grounds (both signal and protective ground) on the
>> user port together on my board, could there be an issue from the 9VAC
>> coming through the ground?   (I'm not using the 9VAC pins themselves,
>> they aren't even connected.)
>>
>> -I'm going through 330 ohm resistors to protect the CIA  (i.e. in case
>> User port and Arduino pins are both outputs).  Could this be putting
>> the TTL signal out of spec on the SX, but not on the 64(C)?
>>
>> I'll post a schematic momentarily, but wanted to ask if anyone has
>> some advice or info as to what the problem might be?
>>
>> Thanks
>> -Leif
>
>
>
> Hey Schema,
> There is a MOD for the expansion port. I can't for the life of me find the
> link at the moment, maybe someone else
> can find it. I DID do the mod on my SX when I had it apart awhile back.
>
>
> ---
> WWW: http://www.commodoredungeon.com
>
> QUOTE : "A Clean bench is a sign of a weak mind."
>
>
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Re: Help with SX64 User Port?

Jim Brain
In reply to this post by Leif Bloomquist
On 10/12/2015 8:21 PM, Leif Bloomquist wrote:

> Following up on my earlier question about using this on an SX64,
> here's the schematic: http://i.imgur.com/OVkLEMG.png
>
> I'm open to other suggestions on the design as well (it's my first PCB
> of any complexity)
>
> Thanks,
> -Leif
>
>
> --
> Leif Bloomquist | [hidden email] | +1 416-737-2328 | Check out
> my blog! http://www.jammingsignal.com
>
> "Every choice, no matter how small, begins a new story." - xkcd
>
>         Message was sent through the cbm-hackers mailing list
I would suggest having a user take scotch tape and cover the user port
pads (all of them).

Then, I would remove the tape on GND and PWR, and the minimal number of
pads to do rs232.  See if that works.

If so, then continue removing tape until the unit fails.  That is the
cultprit.

I know, it sounds cheesy, but it is easy to do, is not permanent, and
anyone can do it.

jim


--
Jim Brain
[hidden email]
www.jbrain.com


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Re: Help with SX64 User Port?

Daniel V. Mackey
In reply to this post by Leif Bloomquist
At 09:25 PM 10/12/2015, you wrote:
>Thanks, I know about the mod  (link is
>http://project64.c64.org/hw/sxuserport.txt, I believe).
>
>I'd hate to have to ask users to mod their SX, especially since an
>EZ232 works on a stock SX64.
>
>Cheers,
>-Leif


Yeah but how many people will use an SX?


---
WWW: http://www.commodoredungeon.com

QUOTE : "A Clean bench is a sign of a weak mind."


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Re: Help with SX64 User Port?

Leif Bloomquist
It's something I want to support, so users can take their SX to
Starbucks and use the free Wi-Fi ;-)   [1]

Seriously, though, I've sold 2 prototype boards so far and the first
thing one user did was try it on an SX.  So there's clearly an
interest in doing so.  Plus now I'm curious why it doesn't work!

[1] https://www.youtube.com/watch?v=dPM9oA72iQw

Cheers,
-Leif



On Mon, Oct 12, 2015 at 9:28 PM, Daniel V. Mackey <[hidden email]> wrote:

>
> Yeah but how many people will use an SX?

> ---
> WWW: http://www.commodoredungeon.com
>
> QUOTE : "A Clean bench is a sign of a weak mind."
>

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Re: Help with SX64 User Port?

Leif Bloomquist
In reply to this post by Jim Brain
Good suggestion.  I have an SX myself and can try this, though I might
start with just recreating the circuit on a protoboard and adding pins
one by one.


On Mon, Oct 12, 2015 at 9:27 PM, Jim Brain <[hidden email]> wrote:

> I would suggest having a user take scotch tape and cover the user port pads
> (all of them).
>
> Then, I would remove the tape on GND and PWR, and the minimal number of pads
> to do rs232.  See if that works.
>
> If so, then continue removing tape until the unit fails.  That is the
> cultprit.
>
> I know, it sounds cheesy, but it is easy to do, is not permanent, and anyone
> can do it.
>
> jim
>
>
> --
> Jim Brain
> [hidden email]
> www.jbrain.com
>
>
>
>       Message was sent through the cbm-hackers mailing list

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RE: Help with SX64 User Port?

landover
In reply to this post by Daniel V. Mackey
I do......

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Daniel V. Mackey
Sent: Tuesday, 13 October 2015 12:29 PM
To: [hidden email]
Subject: Re: Help with SX64 User Port?

At 09:25 PM 10/12/2015, you wrote:
>Thanks, I know about the mod  (link is
>http://project64.c64.org/hw/sxuserport.txt, I believe).
>
>I'd hate to have to ask users to mod their SX, especially since an
>EZ232 works on a stock SX64.
>
>Cheers,
>-Leif


Yeah but how many people will use an SX?


---
WWW: http://www.commodoredungeon.com

QUOTE : "A Clean bench is a sign of a weak mind."


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Re: Help with SX64 User Port?

Gerrit Heitsch
In reply to this post by Leif Bloomquist
On 10/13/2015 03:09 AM, Leif Bloomquist wrote:

> Hi all,
>
> Some of you know I've been tinkering with an Arduino-based Wifi
> "Modem" for the Commodore 64 etc.  (Pics here:
> http://imgur.com/a/ZvwO6)
>
> It's almost ready to go, however, one issue is that it doesn't work on
> the SX64, and it's the same issue on at least two SX's.
>
> The symptom is that while the Arduino receives serial data from the SX
> fine, nothing sent by the Arduino is received by the SX.   I've also
> tried going directly to the Wifi board (which is also serial), same
> issue.   It works fine on a normal 64/64C though.

What kind of CIAs do the different Systems use? At the end of 1986,
Commodore changed the process from NMOS to HMOS-II. For a short while,
some CIAs were labeled '8521R0' but then they went back to the '6526'
label. Usually they were also fast enough for get the 'A' for 2 MHz
operation. The HMOS-II-CIA also changed a bit timingwise, that's where
the legend originated that the 6526A behaves differently than the 6526.

So the question is, does the HMOS-II-CIA work where the NMOS-CIA doesn't?

  Gerrit



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Re: Help with SX64 User Port?

silverdr-2
In reply to this post by Daniel V. Mackey

> On 2015-10-13, at 03:28, Daniel V. Mackey <[hidden email]> wrote:
>
> At 09:25 PM 10/12/2015, you wrote:
>> Thanks, I know about the mod  (link is
>> http://project64.c64.org/hw/sxuserport.txt, I believe).
>>
>> I'd hate to have to ask users to mod their SX, especially since an
>> EZ232 works on a stock SX64.
>>
>> Cheers,
>> -Leif
>
>
> Yeah but how many people will use an SX?

I have quite surprisingly high number of requests regarding DolphinDOS for the SX. It is becoming somewhat more popular among the hobbyists recently, I guess.

--
SD!


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Re: Help with SX64 User Port?

traymond
Hi Leif,

This is a good option for internet access I would use this device.
-Terry Raymond

On Tuesday, October 13, 2015, <[hidden email]> wrote:

> On 2015-10-13, at 03:28, Daniel V. Mackey <<a href="javascript:;" onclick="_e(event, &#39;cvml&#39;, &#39;n2dvm@arrl.net&#39;)">n2dvm@...> wrote:
>
> At 09:25 PM 10/12/2015, you wrote:
>> Thanks, I know about the mod  (link is
>> http://project64.c64.org/hw/sxuserport.txt, I believe).
>>
>> I'd hate to have to ask users to mod their SX, especially since an
>> EZ232 works on a stock SX64.
>>
>> Cheers,
>> -Leif
>
>
> Yeah but how many people will use an SX?

I have quite surprisingly high number of requests regarding DolphinDOS for the SX. It is becoming somewhat more popular among the hobbyists recently, I guess.

--
SD!


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--
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Re: Help with SX64 User Port?

Justin-2
I really like my SX-64 because the keyboard is so much better to type on. Same thing with the 128D. I doubt I'm alone.

Justin

On Oct 13, 2015, at 17:52, Terry Raymond <[hidden email]> wrote:

Hi Leif,

This is a good option for internet access I would use this device.
-Terry Raymond

On Tuesday, October 13, 2015, <[hidden email]> wrote:

> On 2015-10-13, at 03:28, Daniel V. Mackey <<a href="javascript:;" onclick="_e(event, 'cvml', 'n2dvm@arrl.net')">n2dvm@...> wrote:
>
> At 09:25 PM 10/12/2015, you wrote:
>> Thanks, I know about the mod  (link is
>> http://project64.c64.org/hw/sxuserport.txt, I believe).
>>
>> I'd hate to have to ask users to mod their SX, especially since an
>> EZ232 works on a stock SX64.
>>
>> Cheers,
>> -Leif
>
>
> Yeah but how many people will use an SX?

I have quite surprisingly high number of requests regarding DolphinDOS for the SX. It is becoming somewhat more popular among the hobbyists recently, I guess.

--
SD!


       Message was sent through the cbm-hackers mailing list


--
Sent from Gmail Mobile

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RE: Help with SX64 User Port?

hwarin

Exactly the same as you are … In my “office”, I still have a plastic C128D on my desktop and a SX64 right behind me, over a 8250… but no stock C64. In case of any need, I can make tests/measurements on my regular SX and some checks/compare on another one, for spare parts but known to be fully OK.

 

FYI, I have under the hand a “commodoreserver.com” user port to NIC board (rev 2.c). It never appears to be working but the serial to NIC interface (WizNet) was confirmed ok. From what I’ve found on this issue, my commodoreserver board has an issue with 3.3v/5v handling that have been corrected in later revisions.

 

Another possibility for this issue could be cabling … distance from 6526 to user port is far longer with the SX … may be some buffers could help ? a VIC 1011 works well with the SX; you might try with some userportà true RS232 à Arduino interfaces

 

About (Pics here:http://imgur.com/a/ZvwO6) : Nice toy …

 

 


De : owner-[hidden email] [mailto:owner-[hidden email]] De la part de Justin
Envoyé : mercredi 14 octobre 2015 01:19
À : [hidden email]
Objet : Re: Help with SX64 User Port?

 

I really like my SX-64 because the keyboard is so much better to type on. Same thing with the 128D. I doubt I'm alone.

Justin


On Oct 13, 2015, at 17:52, Terry Raymond <[hidden email]> wrote:

Hi Leif,

 

This is a good option for internet access I would use this device.

-Terry Raymond


On Tuesday, October 13, 2015, <[hidden email]> wrote:


> On 2015-10-13, at 03:28, Daniel V. Mackey <<a href="javascript:;">n2dvm@...> wrote:
>
> At 09:25 PM 10/12/2015, you wrote:
>> Thanks, I know about the mod  (link is
>> http://project64.c64.org/hw/sxuserport.txt, I believe).
>>
>> I'd hate to have to ask users to mod their SX, especially since an
>> EZ232 works on a stock SX64.
>>
>> Cheers,
>> -Leif
>
>
> Yeah but how many people will use an SX?

I have quite surprisingly high number of requests regarding DolphinDOS for the SX. It is becoming somewhat more popular among the hobbyists recently, I guess.

--
SD!


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--
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Re: Help with SX64 User Port?

Leif Bloomquist
Thanks everyone.

I found the problem.  The SX doesn't like the 330 ohm current-limiting
resistors on the RX line.  I jumpered it directly and it works.

I'm uncomfortable with not having current-limiting, *especially* on an
SX64 which is such a pain in the butt to repair, so I'm going to
experiment with finding a value that works.

Not sure if the issue is the cable length (as described below), or the
CIA as Gerrit suggested, but at least it's (theoretically) an easy
fix.

I looked into buffers but was unable to find a through-hole
*bidirectional* buffer, so I'll stick with this approach unless
someone has a different solution?

Thanks,
-Leif

--
Leif Bloomquist | [hidden email] | +1 416-737-2328 | Check out
my blog! http://www.jammingsignal.com

"Every choice, no matter how small, begins a new story." - xkcd


On Thu, Oct 15, 2015 at 6:18 PM, hwarin <[hidden email]> wrote:

> Exactly the same as you are … In my “office”, I still have a plastic C128D
> on my desktop and a SX64 right behind me, over a 8250… but no stock C64. In
> case of any need, I can make tests/measurements on my regular SX and some
> checks/compare on another one, for spare parts but known to be fully OK.
>
>
>
> FYI, I have under the hand a “commodoreserver.com” user port to NIC board
> (rev 2.c). It never appears to be working but the serial to NIC interface
> (WizNet) was confirmed ok. From what I’ve found on this issue, my
> commodoreserver board has an issue with 3.3v/5v handling that have been
> corrected in later revisions.
>
>
>
> Another possibility for this issue could be cabling … distance from 6526 to
> user port is far longer with the SX … may be some buffers could help ? a VIC
> 1011 works well with the SX; you might try with some userportà true RS232 à
> Arduino interfaces
>
>
>
> About (Pics here:http://imgur.com/a/ZvwO6) : Nice toy …
>
>
>
>
>
> ________________________________
>
> De : [hidden email]
> [mailto:[hidden email]] De la part de Justin
> Envoyé : mercredi 14 octobre 2015 01:19
> À : [hidden email]
> Objet : Re: Help with SX64 User Port?
>
>
>
> I really like my SX-64 because the keyboard is so much better to type on.
> Same thing with the 128D. I doubt I'm alone.
>
> Justin
>
>
> On Oct 13, 2015, at 17:52, Terry Raymond <[hidden email]> wrote:
>
> Hi Leif,
>
>
>
> This is a good option for internet access I would use this device.
>
> -Terry Raymond
>
>
> On Tuesday, October 13, 2015, <[hidden email]> wrote:
>
>
>> On 2015-10-13, at 03:28, Daniel V. Mackey <[hidden email]> wrote:
>>
>> At 09:25 PM 10/12/2015, you wrote:
>>> Thanks, I know about the mod  (link is
>>> http://project64.c64.org/hw/sxuserport.txt, I believe).
>>>
>>> I'd hate to have to ask users to mod their SX, especially since an
>>> EZ232 works on a stock SX64.
>>>
>>> Cheers,
>>> -Leif
>>
>>
>> Yeah but how many people will use an SX?
>
> I have quite surprisingly high number of requests regarding DolphinDOS for
> the SX. It is becoming somewhat more popular among the hobbyists recently, I
> guess.
>
> --
> SD!
>
>
>        Message was sent through the cbm-hackers mailing list
>
>
>
> --
> Sent from Gmail Mobile

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Re: Help with SX64 User Port?

Gerrit Heitsch
On 10/25/2015 06:05 PM, Leif Bloomquist wrote:
>
> I looked into buffers but was unable to find a through-hole
> *bidirectional* buffer, so I'll stick with this approach unless
> someone has a different solution?

How about a 4066? Yes, it's a switch, but if you just tie the Enable
signal to +5V it becomes a buffer. If it's fast enough for controlling
access to the color RAM in the C64, it should be fast enough anything
I/O-related.

  Gerrit



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Re: Help with SX64 User Port?

Leif Bloomquist
What happens if both sides of a 4066 channel are connected to an
output though?   (since it's possible to configure both the Arduino
and CIA as outputs).



On Sun, Oct 25, 2015 at 1:17 PM, Gerrit Heitsch
<[hidden email]> wrote:

> On 10/25/2015 06:05 PM, Leif Bloomquist wrote:
>>
>>
>> I looked into buffers but was unable to find a through-hole
>> *bidirectional* buffer, so I'll stick with this approach unless
>> someone has a different solution?
>
>
> How about a 4066? Yes, it's a switch, but if you just tie the Enable signal
> to +5V it becomes a buffer. If it's fast enough for controlling access to
> the color RAM in the C64, it should be fast enough anything I/O-related.
>
>  Gerrit
>
>
>
>
>       Message was sent through the cbm-hackers mailing list

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Re: Help with SX64 User Port?

HÁRSFALVI Levente-2
The 4066 merely contains CMOS transfer gates - that is, simple switches
whose series resistances (when open) are in the order of some 1-200
ohms. There are no buffers in the 4066. In the theoretical experiment
below, the open 4066 gate could just be substituted by a regular 1..200
ohm resistor.


On 2015-10-26 22:03, Leif Bloomquist wrote:

> What happens if both sides of a 4066 channel are connected to an
> output though?   (since it's possible to configure both the Arduino
> and CIA as outputs).
>
>
>
> On Sun, Oct 25, 2015 at 1:17 PM, Gerrit Heitsch
> <[hidden email]> wrote:
>> On 10/25/2015 06:05 PM, Leif Bloomquist wrote:
>>>
>>>
>>> I looked into buffers but was unable to find a through-hole
>>> *bidirectional* buffer, so I'll stick with this approach unless
>>> someone has a different solution?
>>
>>
>> How about a 4066? Yes, it's a switch, but if you just tie the Enable signal
>> to +5V it becomes a buffer. If it's fast enough for controlling access to
>> the color RAM in the C64, it should be fast enough anything I/O-related.
>>
>>   Gerrit
>>
>>
>>
>>
>>        Message was sent through the cbm-hackers mailing list
>
>         Message was sent through the cbm-hackers mailing list
>


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Re: Help with SX64 User Port?

HÁRSFALVI Levente-2
One correction: at Vdd=5V (4066), the channel resistance is more likely
  200..1000 ohm (depending on type and manufacturer), rather than 1..200
ohm which'd only apply at Vdd=15V; sorry.


On 2015-10-26 23:09, HÁRSFALVI Levente wrote:

> The 4066 merely contains CMOS transfer gates - that is, simple switches
> whose series resistances (when open) are in the order of some 1-200
> ohms. There are no buffers in the 4066. In the theoretical experiment
> below, the open 4066 gate could just be substituted by a regular 1..200
> ohm resistor.
>
>
> On 2015-10-26 22:03, Leif Bloomquist wrote:
>> What happens if both sides of a 4066 channel are connected to an
>> output though?   (since it's possible to configure both the Arduino
>> and CIA as outputs).
>>
>>
>>
>> On Sun, Oct 25, 2015 at 1:17 PM, Gerrit Heitsch
>> <[hidden email]> wrote:
>>> On 10/25/2015 06:05 PM, Leif Bloomquist wrote:
>>>>
>>>>
>>>> I looked into buffers but was unable to find a through-hole
>>>> *bidirectional* buffer, so I'll stick with this approach unless
>>>> someone has a different solution?
>>>
>>>
>>> How about a 4066? Yes, it's a switch, but if you just tie the Enable
>>> signal
>>> to +5V it becomes a buffer. If it's fast enough for controlling
>>> access to
>>> the color RAM in the C64, it should be fast enough anything I/O-related.
>>>
>>>   Gerrit
>>>
>>>
>>>
>>>
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>>
>>         Message was sent through the cbm-hackers mailing list
>>
>


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Re: Help with SX64 User Port?

Nate Lawson
In reply to this post by Leif Bloomquist
Here’s a summary I wrote up about interfacing. The Circuit Cellar article I linked is quite good.

http://rdist.root.org/2012/01/06/mixed-voltage-interfacing-for-design-or-hacking/

> On Oct 12, 2015, at 6:21 PM, Leif Bloomquist <[hidden email]> wrote:
>
> Following up on my earlier question about using this on an SX64,
> here's the schematic: http://i.imgur.com/OVkLEMG.png
>
> I'm open to other suggestions on the design as well (it's my first PCB
> of any complexity)
>
> Thanks,
> -Leif
>

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