Re: USB to IEC

From: Hans Liss <Hans_at_Liss.pp.se>
Date: Fri, 10 Jan 2020 12:25:30 +0100
Message-ID: <a037c07a-f5df-5d2e-2fa0-b9d5e39d1692_at_Liss.pp.se>
There is a very detailed application note from Philips regarding these 
level shifters: 
https://cdn.sparkfun.com/tutorialimages/BD-LogicLevelConverter/an97055.pdf

As far as I understand it, what Mia describes is explained in section 
2.3.1 State 2.

The newer Pi1541 design uses a 7406 for the output signals and only runs 
the inputs through the BSS138.

/Hans

On 2020-01-10 12:04, Mia Magnusson wrote:
> Den Tue, 7 Jan 2020 11:58:04 -0600 skrev Jim Brain <brain_at_jbrain.com>:
>> On 1/7/2020 4:24 AM, Mia Magnusson wrote:
>>> Btw the level converters Raj Wurttemberg linked to will damage the
>>> PI after a while if using more than one device on the IEC bus (in
>>> addition to the PI), so for example combining a PI1541 with a real
>>> 1541 should be done with the unidirectional active level converters
>>> instead of those passive-ish bidirectional converters.
>> How so?  The FETs are open drain, so do not drive a high voltage at
>> all, they just sink current.
> Afaik all the sink current goes through the PI when using that
> bidirectional converter. Therefore the slightly newer PI1541 hardware
> with unidirectional level converters is the recommendation.
>
Received on 2020-05-30 00:13:46

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