Digi Watchport/T temperature sensor as /dev/ttyU

Tue Aug 9 14:20:13 UTC 2016

On 8/9/2016 09:10, Gary Palmer wrote:
> On Tue, Aug 09, 2016 at 08:28:47AM -0500, Karl Denninger wrote:
>> On 8/9/2016 01:36, O. Hartmann wrote:
>>> On Sun, 24 Jul 2016 13:12:35 -0600
>>> Ian Lepore <ian at freebsd.org> wrote:
>>>
>>>> On Sun, 2016-07-24 at 12:52 -0600, Warner Losh wrote:
>>>>> On Sun, Jul 24, 2016 at 12:42 PM, Kevin Oberman <rkoberman at gmail.com>
>>>>> wrote:  
>>>>>> There are several different USB serial drivers. Off-hand I see
>>>>>> ubser, ubsa,
>>>>>> uchcom, ucom, ucycom, uftdi, ubgensa, umcs, umct, umoscom, uplcom,
>>>>>> usb_serial, uslcom, and uvscom. Whether any of these will support
>>>>>> the TI
>>>>>> chip, I can't say. Most have man pages, but a few, as has been
>>>>>> noted, are
>>>>>> lacking one.  
>>>>> I tried to automate discovery of these things. However, the only way
>>>>> you can really know for sure about the TI chip is to read it's
>>>>> datasheet
>>>>> and compare that with extant drivers. It's actually easier than it
>>>>> sounds.
>>>>>
>>>>> I've often thought of unification of the TTY USB drivers, since they
>>>>> are
>>>>> most (but not all) based on the standard plus extra bits.
>>>>>
>>>>> Warner  
>>>> To reiterate:  we do not have a driver for TI 5052 chips.
>>>>
>>>> It's not much like other usb-serial chips.  In fact it's not strictly a
>>>> usb-serial chip, it's a multifunction chip that includes a software
>>>> -controllable usb hub, 2 serial ports, gpio, an i2c bus master, an MCU
>>>> interface, a multichannel DMA controller, and apparently even has the
>>>> ability to download your own 8052-compatible microcontroller code into
>>>> the 5052 and have it take over from the built-in rom code.
>>>>
>>>> It would be reasonable enough to write a driver that initially
>>>> supported only the uart part of the chip.
>>>>
>>>> -- Ian
>>> Now, that I know that I can not use any of our plenty Digi Watchport/T sensors
>>> with FreeBSD, I'm looking for a cheap alternative of sensor, prefereably being
>>> capable of taking temperature and humidity and being accessed as easy as a
>>> serial terminal - as the Digi Watchport/T does with Linux.
>>>
>>> I still have a "resistance" changing the OS of our infrastructure to Linux due
>>> to ZFS, but the very good support of drivers with the Linux OS is tempting ...
>>> _______________________________________________
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>> Does hardware platform matter?  If not a very inexpensive alternative
>> set is found on Adafruit's site for the Raspberry Pi and FreeBSD can
>> easily talk to either some of the options directly or a cheap ($10)
>> 4-channel 12-bit analog board.  I am using this approach with the Pi2 as
>> a pool controller with multiple temperature inputs and drive (through a
>> relay board) to handle both the VFD-controlled pump motor and valves,
>> plus spa heater.
> If you go down that path the DS 18B20 is a digital temperature probe
> that can be tied to the GPIO pins on a PI and read from python
> quite easily.  Don't think it does humidity, but as the temp. probes
> have a hardware address you can hook multiple up to the same GPIO pin.
>
> If you want humidity also then there is the DHT22 or DHT11, both
> of which can be tied to the PI but need a GPIO pin per sensor.  I 
> haven't tried either of them personally.
>
> Regards,
>
> Gary
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The code to read the Adafruit 12 and 16-bit I2c ADCs is trivial (about a
dozen lines of "C" code) and would allow the use of very inexpensive (a
buck each!) transistor-sized temperature sensors (such as the TMP36)

Here's Adafruit's i2c temp/humidity options -- any of these should be
trivially easy to interface as with the ADC code on the Pi2. One of
these (pick based on your mounting and accuracy requirements) + FreeBSD
+ RPI2 + a bit of code and you're in business.

https://www.adafruit.com/products/165?q=i2c%20humidity&

-- 
Karl Denninger
karl at denninger.net
/The Market Ticker/


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