Thank you for all your responses. a) This is not a high-production product; rather it's a 1 or 2 off custom device for use with an existing system. b) That includes a working 1_Wire(tm) system. It uses multiple Embedded Data System OW-Servers that have 3 channels of 1_Wire devices, and supports multiple high-level TCP/IP protocols; no bit banging needed. c) It works well with multiple devices on long (multiple 100's of ft) twisted pair cable runs. We've not seen any error issues so far. d) The system is based around a custom NXP-based controller. It talks to the EDS's via TCP/IP. It talks to other industrial gear via RS-485. We pondered driving the display via RS-485, but doubt that offers major advantages. There's no available RS-232 on the NXP, even if it would run over the cable run available. Does the above inspire solutions not yet offered? -- A host is a host from coast to coast...............wb8foz@panix.com & no one will talk to a host that's close.......................... Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433
1_Wire display
Started by ●November 29, 2021
Reply by ●December 4, 20212021-12-04
Reply by ●December 4, 20212021-12-04
On 12/3/2021 11:39 PM, David Lesher wrote:> Thank you for all your responses. > > a) This is not a high-production product; rather it's a 1 or 2 > off custom device for use with an existing system. > > b) That includes a working 1_Wire(tm) system. It uses multiple > Embedded Data System OW-Servers that have 3 channels of 1_Wire > devices, and supports multiple high-level TCP/IP protocols; > no bit banging needed. > > c) It works well with multiple devices on long (multiple 100's > of ft) twisted pair cable runs. We've not seen any error issues > so far.That's interesting. Usually, there are noise and ground issues on lengthy runs, esp if DC-coupled.> d) The system is based around a custom NXP-based controller. It > talks to the EDS's via TCP/IP. It talks to other industrial gear > via RS-485. > > We pondered driving the display via RS-485, but doubt that > offers major advantages. There's no available RS-232 on the NXP, > even if it would run over the cable run available. > > Does the above inspire solutions not yet offered?If you think it will work for you -- and is already in line with other "solutions" you've deployed -- then go for it! I've taken to using ethernet over CAT5 for most of my interconnects, now. But, that's primarily because it affords me gobs of bandwidth (which also includes being able to push new firmware on-the-fly) I had cobbled together a "data-over-power" solution to communicate with a repurposed Nest thermostat using the two unused conductors in the thermostat wiring harness but found it quickly ran out of bandwidth. Even encoding terse "commands" that could be executed by the MCU *behind* the Nest (e.g., 0x07 = flash display, 0x08 = display character that follows, 0x09 set color to character that follows...) proved too slugish. So, I replaced the thermostat cable with CAT5e and now I can control the Nest's display in real time (animations, etc. instead of just a static, numeric display). It's still a kludge as I don't have direct control over the Nest's hardware. But, foolish to try to redesign a product that is already so nicely packaged! [IMO, the Nest is the ideal UI for a thermostat. But, *as* a thermostat, I found it sorely lacking!]
Reply by ●December 11, 20212021-12-11
Don Y <blockedofcourse@foo.invalid> writes:>That's interesting. Usually, there are noise and ground issues >on lengthy runs, esp if DC-coupled.>> d) The system is based around a custom NXP-based controller. It >> talks to the EDS's via TCP/IP. It talks to other industrial gear >> via RS-485....>If you think it will work for you -- and is already in line >with other "solutions" you've deployed -- then go for it!So we are NOW looking at using the DS28E18 or DS28E17 1-Wire to I2C chips as it seems there are a metric ****load of displays driven by same: <https://www.aliexpress.com/w/wholesale-2.42-i2c-oled.html> Both are 3.3v which require a bidir level shifter but that's perhaps doable. -- A host is a host from coast to coast...............wb8foz@panix.com & no one will talk to a host that's close.......................... Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433
Reply by ●December 11, 20212021-12-11
On Saturday, December 11, 2021 at 2:02:28 AM UTC-5, David Lesher wrote:> Don Y <blocked...@foo.invalid> writes: > > > >That's interesting. Usually, there are noise and ground issues > >on lengthy runs, esp if DC-coupled. > > >> d) The system is based around a custom NXP-based controller. It > >> talks to the EDS's via TCP/IP. It talks to other industrial gear > >> via RS-485. > ... > >If you think it will work for you -- and is already in line > >with other "solutions" you've deployed -- then go for it! > So we are NOW looking at using the DS28E18 or DS28E17 1-Wire to > I2C chips as it seems there are a metric ****load of displays > driven by same: > > <https://www.aliexpress.com/w/wholesale-2.42-i2c-oled.html> > > Both are 3.3v which require a bidir level shifter but that's perhaps > doable."Quickswitch" is a brand name I believe, but there are multiple sources. Or you can roll your own with a FET on each of the clock and data lines. Tie the gate of a MOSFET to the 5 volt rail through a diode and you should get the right switching voltage to disable the channel for any input greater than about 3 volts. Or use one of the switch based logic interface parts. It essentially creates a bi-dir drive that is totem pole up to about 3 volts and is open drain above that. So you get the rapid rise in voltage through the full 3 volt range with no issues of over voltage on the 3.3 volt side. I strongly recommend you avoid Aliexpress though. Find other sources. Aliexpress is not there for the buyers. -- Rick C. -- Get 1,000 miles of free Supercharging -- Tesla referral code - https://ts.la/richard11209
