> 22 juli 2016 kl. 13:25 skrev Jan Kandziora <j...@gmx.de>: > >> Am 22.07.2016 um 12:30 schrieb Henrik Östman: >> Hi! >> >> I have a self soldered circuit board containing a DS2480 and a >> Max232-converter, back in the old days it was connected directly to the >> serialport of a computer but nowdays I'm using a USB-serial converter >> connected to a Raspberry Pi. Thinking about it it makes no sense >> converting the signal to a RS232-level and back again, it only makes the >> installation more complex and more troublesome to faultfinding. >> Should'nt it be possible to connect the DS2480 directly to one/two pins >> on the Raspberry > The GPIO pins of the Raspberry are 3.3V. The DS2480B is not compatible > to 3.3V, you need a 3.3V->5V level shifter. This can be an IC, or two > MOSFETS (e.g. BS170, 2N7000) and two 1.5k to 4.7k resistors on the TxD > and RxD lines. Do you need the 12V EPROM programming? > Yes I keep forgetting its 3.3v, and with the need of levelshifters I could just as well start over with a I2C chip (buy a finished card for the Pi). No I don't need eeprom, my card support it but I never used it.
> Because the easiest way to have Onewire on the Raspberry is using GPIO4 > and let the w1 kernel driver bitbang the protocol. If you want a 5V > Onewire, you need a single MOSFET and resistor again as the level > shifter. Note: no strong pullup available with 5V level shifting in this > case. > > I never liked the bitbang and simple resistor pullup solution, never got it > working good in big and critical networks. The ds2480 is a real solid chip, I > like it, too bad the I2C ones are not that strong. > The alternative I recommend is to use the DS2483. It's 3.3V compatible > on its I2C inputs and gives you a 5V Onewire with all features but 12V > EPROM programming on its output. Plus, the single RS232 port the > Raspberry has stays free for console and other purposes. > > >> and use a suitable driver? Could anyone point me to >> which driver to use, how should owfs.conf be setup to support this, and >> which pins on the Raspberry Pi should I connnect to? > Choose your poison first. > So basically you are saying, throw away my old card and use a I2C instead. 😄 And I think your right. > > Kind regards > > Jan > ------------------------------------------------------------------------------ What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports.http://sdm.link/zohodev2dev _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers
