[GreenKeys] ESP8266 WiFi Module UART

[Chris Elmquist]

On Wednesday (12/23/2015 at 03:44PM -0500), Steve Garrison wrote:
> Hi Javier!
> 
> This appears to be a WIFI product.  Am I missing something?  UART on a WIFI
> product?

Yes indeed.  These are a WiFi module with full TCP stack in the firmware
and can be used as a complete wireless terminal server.  I have been
playing with them and with this alternative firmware load for some time,

https://github.com/jeelabs/esp-link

but I have not dug deep enough to try to change them to the very slow
baud rates needed for old TTY connections.  My guess is that they might
not do it because they run from a very high clock rate in order have
a lot of CPU horsepower which typically results in not being able to
divide the clock feeding the UART down enough to get the slow speeds.

I typically solve that problem by putting another small processor (such as
ATMEL AVR (ATTiny2313 to be specific) in between and implement the speed
conversion, buffering and flow control there...  connecting to the WiFi
(or serial to ethernet alternatively) device at a more modern rate such
as 115200.

So, it looks like,

        TTY <-- 45 baud --> AVR <-+- 115K baud -+-> WIFI or ETHERNET
                                  |- RTS/CTS  --| 

Chris NØJCF

> -----Original Message-----
> From: GreenKeys [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of
> Javier Albinarrate
> Sent: Wednesday, December 23, 2015 1:30 PM
> To: greenkeys at mailman.qth.net
> Subject: [GreenKeys] ESP8266 WiFi Module UART
> 
> Hello folks,
> 
> This is probably just a big wish for Christmas... but anyway...
> Has anyone tried this module to see if its UART can be set to low baud rates
> and 5/6/7 bits? Perhaps by tweaking its firmware? In the end there must be
> registers, multipliers and divisors somewhere.
> 
> https://www.sparkfun.com/products/13678
> 
> They have a forum, http://www.esp8266.com/ but I have not seen in depth
> manuals so far.
> 
> Regards!
> 
> Javier Albinarrate
> LU8AJA
> ______________________________________________________________
> GreenKeys mailing list
> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:GreenKeys at mailman.qth.net
> 
> 2002-to-present greenkeys archive:
> http://mailman.qth.net/pipermail/greenkeys/
> 1998-to-2001 greenkeys archive:
> http://mailman.qth.net/archive/greenkeys/greenkeys.html
> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
> http://comcents.com/tty/greenkeyssearch.html
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html Message
> delivered to steve.n4tty at gmail.com
> 
> ______________________________________________________________
> GreenKeys mailing list
> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:GreenKeys at mailman.qth.net
> 
> 2002-to-present greenkeys archive: http://mailman.qth.net/pipermail/greenkeys/
> 1998-to-2001 greenkeys archive: http://mailman.qth.net/archive/greenkeys/greenkeys.html
> Randy Guttery's 2001-to-2009 GreenKeys Search Tool: http://comcents.com/tty/greenkeyssearch.html
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to chrise at pobox.com

-- 
Chris Elmquist