[NTLK] Newton gateway idea

David Arnold davida at pobox.com
Sun Jan 10 16:02:34 EST 2016


> On 10 Jan 2016, at 17:55, Randy Glenn <randy.glenn at gmail.com> wrote:

Hi Randy,

> On Fri, Jan 8, 2016 at 11:37 PM, David Arnold <davida at pobox.com> wrote:
> 
>> Back in the day, there were PCMCIA serial cards from a company called
>> “Socket Communications” (I think?) that were supported out-of-the-box by
>> NOS.  A quick search suggests that some form of that company still exists
>> selling mobile-related stuff, so it might be possible to get a hold of
>> their cards.  But I *think* they were really just low-power,
>> 16550-compatible, basic serial/UART cards.  So it *might* be pretty easy to
>> build a PCMCIA card with a suitable UART chip that works with NOS without
>> any additional effort.
>> 
>> 
> http://www.ti.com/product/tl16pc564b is probably a good chip for this (at
> least, it's the first purpose-built one I found)

Thanks!  It does sound like it’s built for the job.

>> I used to use NIE’s PPP to a Linux box on a regular basis, and my
>> recollection is that it worked without any real issues.
>> 
>> Rather than requiring two serial ports, once you’ve got PPP running, you
>> can use PT100 to telnet into the Linux box.  My plan was a expose
>> configuration through an old-skool HTML-2/HTTP-1.0 web site that could be
>> easily grokked by NetHopper …
>> 
>> 
> My concern about using Telnet is that if the PPP server isn't working,
> you've got a brick on your hand. Having an extra UART available for
> debugging would make things easier.

True.  Perhaps a dongle socket on the external-facing end, with UART (and probably JTAG) exposed would be best?  An onboard USB-serial converter would make life simple: connect the appropriate cable and plug it directly into a laptop for bootloader/console access.

>>> Going with a Type III PCMCIA card form factor should allow space for a
>>> Linux system and the serial hardware, while still fitting into an eMate.
>>> A Pi Zero might fit in that form factor.
>>> 
>> Type III rules out the MP2k’s, so I was hoping to get a Type II (ie. 5mm
>> high) form factor to work.
>> 
>> 
> Trickier to pull off, but the possibilities are pretty awesome.

Ack.

>>> Actually pulling it off is another matter entirely, of course - a lot of
>>> PCMCIA stuff is now end-of-life.
>> 
>> Yes.  So the next year or so is probably a critical time to buy EOLed
>> components if it’s ever going to be possible.
> 
> 
> It looks like that TI chip is last time buy, with a deadline of March 26.
> The unit cost is $14, with a minimum quantity of 90. Ick.

If I’m reading it right, it looks like Rochester has them available, minimum quantity of 10 at about $10 each.

   https://www.rocelec.com/parts/details/?part=569056cde4b0e3ba41657b7a&build=0


> A cheaper method might be to use an FPGA as the UART(s) and PCMCIA
> interface. That combined with something like the RT5350 router chip (runs
> Linux, 360 MHz MIPS core, up to 64 MB RAM, WiFi, and very cheap) might do
> it.

I wondered whether using an FPGA for the whole thing might be sensible: a Zynq or similar with a hard-IP CPU that’d be sufficient for the Linux box, and the rest of the required hardware can be synthesised.  The FPGA would make potential future enhancements possible as well.

My VHDL/Verilog skills are non-existent (does owning a book count?) but …




d



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