Re: Help with SX64 User Port?

From: HÁRSFALVI Levente <publicmailbox_at_harsfalvi.net>
Date: Mon, 26 Oct 2015 23:20:42 +0100
Message-ID: <562EA73A.80901@harsfalvi.net>
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
>> <gerrit@laosinh.s.bawue.de> 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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Received on 2015-10-26 23:00:47

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