On Friday 05 May 2017 02:29:56 Erik Christiansen wrote: > On 04.05.17 20:43, Gene Heskett wrote: > > On Thursday 04 May 2017 13:47:22 Chris Albertson wrote: > > > Yes I agree conversion is cheap and easy, You can buy the Max > > > chips on breakout boards with connectors for 50 cents each > > > ebay.com/itm/2PCS-MAX485-Module > > > <http://www.ebay.com/itm/2PCS-MAX485-Module-RS-485-Module-TTL-to-R > > >S-48 > > > 5-Converter-For-Arduino/131694536431?_trksid=p2047675.c100005.m185 > > >1&_tr > > > kparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D40130%26meid > > >%3De5 > > > 19e5e6252c4e40b7d0fa2b19dcd5fc%26pid%3D100005%26rk%3D6%26rkt%3D6%2 > > >6meho t%3Dag%26sd%3D112076449800> In most cases it is best to buy > > > the chips on boards with connectors. Saves you from a lot of > > > work. > > That's a good find. I may buy a few, just to breadboard with before I > get around to doing a board with ATmega328P and RS485 chip in one. > > > I agree. The only problem with this board is that its rs485 only. > > Unbalanced IOW. > > No, not so, Gene. As already pointed out, RS485 is the multipoint > version of RS422, so balanced enough to pass a "walk the dotted line" > DUI test. ;-) Seriously, the 'A' and 'B' balanced line labels can be > seen on the PCB at the above link.
If the above link= <http://www.ebay.com/itm/2PCS-MAX485-Module-RS-485-Module-TTL-to-RS-485-Converter-For-Arduino/131694536431?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D40130%26meid%3De519e5e6252c4e40b7d0fa2b19dcd5fc%26pid%3D100005%26rk%3D6%26rkt%3D6%26mehot%3Dag%26sd%3D112076449800> Yes, I see that now. That I assume means its half-duplex, but the spi is too. Thats a great price. There is also this 5 pack available: <http://www.ebay.com/itm/5-MAX485-Module-RS485-Module-TTL-to-RS-485-Module-Converter-Board-TS/172176974958?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D40130%26meid%3D23e1633c0ba04d319d14c7ad895cf7e1%26pid%3D100005%26rk%3D1%26rkt%3D6%26sd%3D13169453> Now, do we have an hm2 driver for the pi's gpio? And in one of the adds it mentions slew rate limited, so I wonder what its top speed is? And if that slew rate is in the form of a capacitor, could it be removed? Has anyone here used this one? What for & how fast? Since this stuff is best described as volatile, I'll buy the 5 pack so I've some to "play with". Lots of questions... > ... > > > And its data rate must be pretty slow, its slew rated but not in any > > usefull way. > > Ah, yes, the MAX485 will limit you to 2.5 Mb/s, and tolerance of > "improperly terminated cables" isn't something we'd need. The jabber > about "reduced EMI" sounds dubious too, as properly terminated twisted > pair ought not radiate alarmingly. > > > > People are using Cat5 (Ethernet cable) for all types of serial > > > links now. It just works better as most links are now balanced > > > pairs. > > Yes, a reel of that stuff is buried somewhere in any good components > stash, I hold. > > Erik > > ---------------------------------------------------------------------- >-------- Check out the vibrant tech community on one of the world's > most engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
