OneWire ALPHA
#61
Posted 07 July 2011 - 11:04 AM
#62
Posted 07 July 2011 - 07:23 PM
I figured it out.
// Instruct a single DS18*20 to do a temperature conversion and read result. public static void GetSingleTemperature(byte[] romAddess) { var oneWire = new OneWire(Pins.GPIO_PIN_D0); // Adjust the pin if necessary if(oneWire.Reset()) { // DS18B20 Thermometer oneWire.WriteByte(OneWire.MatchRom); // Address single device oneWire.Write(romAddress); // 64bit ROM code stored in byte[] romAddress oneWire.WriteByte(DS18B20.ConvertT); Thread.Sleep(750); // Wait Tconv (for default 12-bit resolution) oneWire.Reset(); oneWire.WriteByte(OneWire.MatchRom); // Address single device oneWire.Write(romAddress); // 64bit ROM code stored in byte[] romAddress oneWire.WriteByte(DS18B20.ReadScratchpad); // Read just the temperature (2 bytes) var tempLo = oneWire.ReadByte(); var tempHi = oneWire.ReadByte(); var temp = DS18B20.GetTemperature(tempLo, tempHi); // ((short)((tempHi << 8) | tempLo))/16F Debug.Print(temp.ToString()); } } // Get temperature reading from all devices on the bus. public statis void EnumerateAllDeviceTemps() { var rom = new byte[8]; // 64-bit var deviation = 0; // Search result do { if((deviation = oneWire.Search(rom, deviation)) == -1) break; if(OneWire.ComputeCRC(rom, count:7) == rom[7]) { // Found a valid device ID GetSingleTemperature(rom); } } while(deviation > 0); }
#63
Posted 11 July 2011 - 03:45 PM
#64
Posted 12 July 2011 - 12:13 AM
Any chance supporting DHT11/DHT22 humidity and temperature sensors? They're not one-wire, but the communication is similar and needs to be done native, not in managed C# code. I see Steve88W wrote earlier in this topic that there is a "huge step closer to supporting the DHT11 and DHT22". Any progress on that?
Add one for DHT11 sensors support.
#65
Posted 22 July 2011 - 02:19 PM
Hi phantom, grimbouk:
When the .NET MF 4.2 firmware is finished in the next month or so, we'll be happy to build a custom version with CW2's latest OneWire feature...for Netduino, Netduino Plus, and Netduino Mini.
Chris
Chris, I've been running the 1-Wire stuff now for a month, reading 7+ sensors on 2 different Netduinos and it is solid. It is easily one of the most reliable parts of my system. I would encourage you to include the current+tested version in the next release and save CW2's enhanced version for the next Alpha/Beta build...
Thanks,
Valkyrie-MT
#66
Posted 11 August 2011 - 03:35 AM
#67
Posted 11 August 2011 - 06:51 AM
Hello Scott, you can unzip the files anywhere you want. The sample application (OneWireTestApp.csproj) has set all needed dependencies (projects, dlls), which are build automatically and deployed to your Netduino. If you want to use OneWire class in your own project, add a reference to CW.NETMF.OneWire.dll (i.e. from "...\Netduino_v4.1.1_beta1_CW.NETMF.OneWire-1.0.5.0\Solutions\Netduino\Interop\CW_NETMF_OneWire\ManagedCode\bin\Release\le\" directory)....but can you tell me where I unzip the files for the example program prior to build and deploy?
Hope this helps.
#68
Posted 13 August 2011 - 10:22 AM
#69
Posted 13 August 2011 - 05:49 PM
#70
Posted 13 August 2011 - 06:34 PM
IMHO the problem is that your oneWire object uses pin D0 that also has alternative function of being RxD of COM1 and it tries to reserve it during its initialization, which results in exception. To resolve the issue, you can use different pin for OneWire, e.g. D2, or switch to COM2 (D2, D3) for serial communication.I'm trying to use the serial port to control a SparkFun serial LCD, and use the OneWire support of this firmware at the same time.
#71
Posted 13 August 2011 - 06:35 PM
...I am using the .Net Micro Framework 4.2 RC...Is there some OneWire function in it? Where can i find more information on Netduino Plus hardware support?
There is no one-wire support built into the Netduino 4.2 RC1 firmware, but we build make a version with OneWire support shortly after the .NET MF 4.2 is completed (out of beta).
Welcome to the Netduino community,
Chris
#72
Posted 13 August 2011 - 06:37 PM
Edited by Chris Walker, 13 August 2011 - 06:37 PM.
CW2 beat me to it! Thanks, CW2. He's correct as usual :)
#73
Posted 13 August 2011 - 07:38 PM
IMHO the problem is that your oneWire object uses pin D0 that also has alternative function of being RxD of COM1 and it tries to reserve it during its initialization, which results in exception. To resolve the issue, you can use different pin for OneWire, e.g. D2, or switch to COM2 (D2, D3) for serial communication.
CW2, That did it! Thanks!
Scott...
#74
Posted 14 August 2011 - 06:04 AM
FANTASTIC! The One-Wire code in the firmware appears solid to me. I haven't seen any issues with it. Although, I really wanted to see a much simpler and object oriented way of working with 1 wire, so I wrote a wrapper class (called OneWireNetwork) out of CW2's sample. I only tested it with my DS18B20 sensors, but I have more coming soon and hopefully will add classes for them. So, what I did was create a collection class of devices that has a "Discover" method to scan the One-Wire network for devices. I hope this can be the start of a One-Wire framework that will make this the easiest One-Wire platform available. I have attached the code to this post. It is a complete replacement for CW2's OneWireTestApp project from the first post. Also, this example works with 1, 2, 3, or more devices, using parasite power or not.
By using the library, the code gets very simple:
public static void Main() { // TODO: Change pin according to the actual wiring var deviceNetwork = new OneWireNetwork(Pins.GPIO_PIN_D0); // Interrogate the devices on the network (adding them to the collection) deviceNetwork.Discover(); while (true) { // Loop through all the discovered devices foreach (var aDevice in deviceNetwork) { Debug.Print("Address: " + aDevice.Address); if (aDevice is DS18B20) Debug.Print("Temp: " + (aDevice as DS18B20).Temperature); } Thread.Sleep(20000); } }
Output:
1-Wire device present Multiple devices present 72000002DC320128 B2000002DC405128 54000002DC577D28 Address: 000002DC3201 Temp: 23.375 Address: 000002DC4051 Temp: 23.4375 Address: 000002DC577D Temp: 23.5 The program '[16] Micro Framework application: Managed' has exited with code 0 (0x0).
Things still to add:
Support for reading and writing to the device memory
Throw Events for device alerts
Robust exception handling
Throw Events for devices being added or removed
Support for a variety of One-Wire devices
Automatic instantiation of classes based on detected device family (should probably use some Reflection here)
I think CW2's firmware should get included into the next Beta. Let's get more people trying to use it...
*** Thanks again to CW2 ***
-Valkyrie-MT
Valkyrie,
I noticed that ever time you call Discover() it causes "foreach (var aDevice in gdeviceNetwork)" to add a new device to gDeviceNetwork...
May be intended, but if you put the discover in a loop, it adds a new device for every 1wire device you have on the network each time you call it. Seems like you should put a CRC check to make sure that the same device is not being added for each call...
FYI: I moved the Discover() call outside the loop, once at the top of Main() and it solved my problem..
Scott...
#75
Posted 14 August 2011 - 02:29 PM
I noticed that ever time you call Discover() it causes "foreach (var aDevice in gdeviceNetwork)" to add a new device to gDeviceNetwork...
That was a very early implementation. I fixed a few thing and have added the CRC checking as well. Unfortunately, code specific to my project creaped into my implementation and I haven't had time to factor it back out. But, I can say that the API is capable of everything I wanted and is very reliable.
-Valkyrie-MT
#76
Posted 14 August 2011 - 11:57 PM
Not entirely sure I understand your question, so I'll try to answer with some observations/facts.
- You must have this native driver to directly communicate with 1-wire devices (parasitic or not) with the Netduino (alternatively, you can use components like those from Peter Anderson)
- With this firmware, I can read from a mix of DS18B20, DS18S20, DS18B20PAR sensors some connected in parasitic mode (only 2 wires - ground and 1-wire signal) and others connected with the 5VDC (non-parasitic). I currently have 5 sensors connected - 3 are not parasitic and 2 are parasitic. That works fine.
- On occassion, I will get a bad read (think 1 in 50 reads) for whatever reason (possibly because I don't have a MOSFET as recommended), but with the CRC check, you always know, so I handle them easily. And usually, it won't happen twice on the same sensor.
-Valkyrie-MT
Valkyrie,
Can you elaborate on the CRC fix you are using to deal with the bad reads? I am getting some bogus temp readings as well..
Scott...
#77
Posted 15 August 2011 - 04:24 AM
Can you elaborate on the CRC fix you are using to deal with the bad reads? I am getting some bogus temp readings as well..
For instance with temperature sensors, I've found that there are 2 kinds of bogus values. Ones corrupted in transmission (will fail CRC) and incomplete calculations from the sensors (which returns a default value that passes CRC). So, what I do is maintain the last sensor value in a variable and give that when requested. While at the same time, I routinely try to update the value. Below is the actual code I use for the sensor read with CRC and uninitialized value checking...
// Write command and identifier at once var matchRom = new byte[9]; Array.Copy(_rom, 0, matchRom, 1, 8); matchRom[0] = OneWire.MatchRom; _core.Reset(); _core.Write(matchRom); _core.WriteByte(DS18X20.ReadScratchpad); System.Threading.Thread.Sleep(5); // Wait Tconv (for default 12-bit resolution) var response = new byte[9]; var status = _core.Read(response); var CRCPass = OneWire.ComputeCRC(response, count: 8) == response[8]; var Initialized = OneWireExtensions.BytesToHexString(response.Range(0, 1)) != "0550"; if (status == 9 && CRCPass && Initialized) { if (this.FamilyCode == 0x28) { _lastTemp = ((short)((response[1] << 8) | response[0])) / 16F; } else if (this.FamilyCode == 0x10) { _lastTemp = (float)(((short)((response[1] << 8) | response[0])) >> 1) - 0.25F + ((float)(response[7] - response[6]) / (float)response[7]); } _lastTempTime = DateTime.Now; Debug.Print("Getting DS18X20 Temp - " + this.Address + ", " + _lastTemp.ToString()); }
Also, the .Range method is just an extension method that returns an arrange of the requested range.
-Valkyrie-MT
#78
Posted 11 September 2011 - 06:39 PM
#79
Posted 14 September 2011 - 01:37 AM
#80
Posted 14 September 2011 - 03:00 AM
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