Easiest way to interface with a Raspberry

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Easiest way to interface with a Raspberry

Henrik Östman
Hi!

I have a self soldered circuit board containing a DS2480 and a
Max232-converter, back in the old days it was connected directly to the
serialport of a computer but nowdays I'm using a USB-serial converter
connected to a Raspberry Pi. Thinking about it it makes no sense
converting the signal to a RS232-level and back again, it only makes the
installation more complex and more troublesome to faultfinding.
Should'nt it be possible to connect the DS2480 directly to one/two pins
on the Raspberry and use a suitable driver? Could anyone point me to
which driver to use, how should owfs.conf be setup to support this, and
which pins on the Raspberry Pi should I connnect to?

Many thanks!


// Henrik


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Re: Easiest way to interface with a Raspberry

Jan Kandziora
Am 22.07.2016 um 12:30 schrieb Henrik Östman:

> Hi!
>
> I have a self soldered circuit board containing a DS2480 and a
> Max232-converter, back in the old days it was connected directly to the
> serialport of a computer but nowdays I'm using a USB-serial converter
> connected to a Raspberry Pi. Thinking about it it makes no sense
> converting the signal to a RS232-level and back again, it only makes the
> installation more complex and more troublesome to faultfinding.
> Should'nt it be possible to connect the DS2480 directly to one/two pins
> on the Raspberry
>
The GPIO pins of the Raspberry are 3.3V. The DS2480B is not compatible
to 3.3V, you need a 3.3V->5V level shifter. This can be an IC, or two
MOSFETS (e.g. BS170, 2N7000) and two 1.5k to 4.7k resistors on the TxD
and RxD lines. Do you need the 12V EPROM programming?


Because the easiest way to have Onewire on the Raspberry is using GPIO4
and let the w1 kernel driver bitbang the protocol. If you want a 5V
Onewire, you need a single MOSFET and resistor again as the level
shifter. Note: no strong pullup available with 5V level shifting in this
case.


The alternative I recommend is to use the DS2483. It's 3.3V compatible
on its I2C inputs and gives you a 5V Onewire with all features but 12V
EPROM programming on its output. Plus, the single RS232 port the
Raspberry has stays free for console and other purposes.


> and use a suitable driver? Could anyone point me to
> which driver to use, how should owfs.conf be setup to support this, and
> which pins on the Raspberry Pi should I connnect to?
>
Choose your poison first.


Kind regards

        Jan


------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity planning
reports.http://sdm.link/zohodev2dev
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Re: Easiest way to interface with a Raspberry

CReese
Second ds2483. Cheap too.

> On Jul 22, 2016, at 4:25 AM, Jan Kandziora <[hidden email]> wrote:
>
>> Am 22.07.2016 um 12:30 schrieb Henrik Östman:
>> Hi!
>>
>> I have a self soldered circuit board containing a DS2480 and a
>> Max232-converter, back in the old days it was connected directly to the
>> serialport of a computer but nowdays I'm using a USB-serial converter
>> connected to a Raspberry Pi. Thinking about it it makes no sense
>> converting the signal to a RS232-level and back again, it only makes the
>> installation more complex and more troublesome to faultfinding.
>> Should'nt it be possible to connect the DS2480 directly to one/two pins
>> on the Raspberry
> The GPIO pins of the Raspberry are 3.3V. The DS2480B is not compatible
> to 3.3V, you need a 3.3V->5V level shifter. This can be an IC, or two
> MOSFETS (e.g. BS170, 2N7000) and two 1.5k to 4.7k resistors on the TxD
> and RxD lines. Do you need the 12V EPROM programming?
>
>
> Because the easiest way to have Onewire on the Raspberry is using GPIO4
> and let the w1 kernel driver bitbang the protocol. If you want a 5V
> Onewire, you need a single MOSFET and resistor again as the level
> shifter. Note: no strong pullup available with 5V level shifting in this
> case.
>
>
> The alternative I recommend is to use the DS2483. It's 3.3V compatible
> on its I2C inputs and gives you a 5V Onewire with all features but 12V
> EPROM programming on its output. Plus, the single RS232 port the
> Raspberry has stays free for console and other purposes.
>
>
>> and use a suitable driver? Could anyone point me to
>> which driver to use, how should owfs.conf be setup to support this, and
>> which pins on the Raspberry Pi should I connnect to?
> Choose your poison first.
>
>
> Kind regards
>
>    Jan
>
>
> ------------------------------------------------------------------------------
> What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
> patterns at an interface-level. Reveals which users, apps, and protocols are
> consuming the most bandwidth. Provides multi-vendor support for NetFlow,
> J-Flow, sFlow and other flows. Make informed decisions using capacity planning
> reports.http://sdm.link/zohodev2dev
> _______________________________________________
> Owfs-developers mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/owfs-developers

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patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity planning
reports.http://sdm.link/zohodev2dev
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Re: Easiest way to interface with a Raspberry

Henrik Östman
In reply to this post by Jan Kandziora


> 22 juli 2016 kl. 13:25 skrev Jan Kandziora <[hidden email]>:
>
>> Am 22.07.2016 um 12:30 schrieb Henrik Östman:
>> Hi!
>>
>> I have a self soldered circuit board containing a DS2480 and a
>> Max232-converter, back in the old days it was connected directly to the
>> serialport of a computer but nowdays I'm using a USB-serial converter
>> connected to a Raspberry Pi. Thinking about it it makes no sense
>> converting the signal to a RS232-level and back again, it only makes the
>> installation more complex and more troublesome to faultfinding.
>> Should'nt it be possible to connect the DS2480 directly to one/two pins
>> on the Raspberry
> The GPIO pins of the Raspberry are 3.3V. The DS2480B is not compatible
> to 3.3V, you need a 3.3V->5V level shifter. This can be an IC, or two
> MOSFETS (e.g. BS170, 2N7000) and two 1.5k to 4.7k resistors on the TxD
> and RxD lines. Do you need the 12V EPROM programming?
>
Yes I keep forgetting its 3.3v, and with the need of levelshifters I could just as well start over with a I2C chip (buy a finished card for the Pi).
No I don't need eeprom, my card support it but I never used it.

> Because the easiest way to have Onewire on the Raspberry is using GPIO4
> and let the w1 kernel driver bitbang the protocol. If you want a 5V
> Onewire, you need a single MOSFET and resistor again as the level
> shifter. Note: no strong pullup available with 5V level shifting in this
> case.
>
> I never liked the bitbang and simple resistor pullup solution, never got it working good in big and critical networks. The ds2480 is a real solid chip, I like it, too bad the I2C ones are not that strong.

> The alternative I recommend is to use the DS2483. It's 3.3V compatible
> on its I2C inputs and gives you a 5V Onewire with all features but 12V
> EPROM programming on its output. Plus, the single RS232 port the
> Raspberry has stays free for console and other purposes.
>
>
>> and use a suitable driver? Could anyone point me to
>> which driver to use, how should owfs.conf be setup to support this, and
>> which pins on the Raspberry Pi should I connnect to?
> Choose your poison first.
>
So basically you are saying, throw away my old card and use a I2C instead. 😄 And I think your right.
>
> Kind regards
>
>    Jan
>

------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity planning
reports.http://sdm.link/zohodev2dev
_______________________________________________
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