OK, Christian ... first of all, thanks for your valuable input.
If I understand it correctly, only 4 pins (2,3,4,5) of standard DB-9 are used to build an equivalent DS9097 circuit for 1-wire chips, of which DTR (pin 4) connects to 1-wire Data (probably DQ for Maxim 1-wire chip), and RXD (pin 2) connects to 1-wire GND (probably P- for Maxim 1-wire chip). So, with those diodes and resistors in the picture (protection circuit for the 1-wire chip), I've decided to build my own little circuit for 4-pin for my board (and not using off-the-shelf 9-pin DS9097). Conceptually it should work (help me if I am missing anything): DTR (of DB9) is equivalent to Vcc (my board), RX and TX (of DB9) are equivalent to TX and RX (my board), respectively, and GND to GND, of course with an equivalent protection circuit, as shown in the picture. With this (1-wire chip with my own circuit for 4-pin serial above, which I presume will be equivalent to DS9097), I guess owfs would be able to see and mount the /dev/ttyS0, and would NOT complain: "Could not detect DS9097". Any input from you will be useful before I jump into it. Another question: what about the other pins of DB9 as shown in the picture? Are they left open, especially handshaking pins like RTS/CTS (pin 7/8)? Thanks. ---- Christian Magnusson-2 wrote: > > Shouldn't you be able to use Maxim's reference design of a passive 9097 > adapter? > > DTR is there to supply 1-wire bus with power since it's high when > serial-port is opened. This could be replaced with Vcc I think. Perhaps an > extra 100ohm (just after Vcc) to protect it from short-circuit would be > good too. The DTR pin is probably short-protected on all > serial-interfaces, > but Vcc on your board is probably not. > > > > Look at the drawing at: > > http://owfs.sourceforge.net/adapters.html#Serial > > Picture: <http://owfs.sourceforge.net/adapters/adapter.gif> > http://owfs.sourceforge.net/adapters/adapter.gif > > > > /Christian > > > > > > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of suman > sarkar > Sent: den 12 september 2007 01:59 > To: owfs-developers@lists.sourceforge.net > Subject: [Owfs-developers] Re :Re: Re :Re: MIPS vs MIPSEL in OWFS > > > > Hi Christian, > > Here are some clarifications re: Meraki AP's serial interface. > > This interface is NOT a regular 9-pin interface (DB9) as you see in > WRT54G. > It has only 4 pins: Vcc, Tx, Rx, and GND. > > OWFS can only support DS9097 serial adapter, I presume, which has a > regular > 9-pin serial configuration. > > So, any Maxim sensor chip (which is DS2781K in our case), with DS9097 > serial adapter CAN NOT be directly fed to the AP's 4-pin interface. It > needs > some tweaking, I guess. > > Any suggestion regarding how to make it compatible with a 4-pin > interface? > > Thanks. > > > > > > > > > <http://adworks.rediff.com/cgi-bin/AdWorks/click.cgi/www.rediff.com/signatur > e-home.htm/[EMAIL PROTECTED]/1436607_1430041/1436126/1?PARTNER=3&OAS_QUERY= > null%20target=new%20> cashback_rediff_signatureli_578x38 > > > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2005. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Owfs-developers mailing list > Owfs-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/owfs-developers > > -- View this message in context: http://www.nabble.com/Re-%3ARe%3A--Re-%3ARe%3A--MIPS-vs-MIPSEL-in-OWFS-tf4426220.html#a12646770 Sent from the OWFS - Dev mailing list archive at Nabble.com. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers
