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#54170 i2c bus speed? Is there a limit beyond 400kHz?

Posted by philvr on 19 November 2013 - 11:04 AM in Netduino Plus 2 (and Netduino Plus 1)

Thanks. I should have read the data sheet...

 

Another question is just how reliable is the netduino I2C firmware? Has anyone stress tested the i2c implementation? As I am moving toward a commercial product it would be interesting to develop an idea of how robust it is.




#54150 i2c bus speed? Is there a limit beyond 400kHz?

Posted by philvr on 18 November 2013 - 04:45 PM in Netduino Plus 2 (and Netduino Plus 1)

I've had two MCP23017 digital i/o chips running well at 400kHz. But running at 1MHz is unsuccessful. I've tried tweaking the bus pull up resistors. Has anyone run I2C at 1MHz? Or Faster? I'd like to know what can be achieved. NDP2 with f/w 4.2.2.2 using MultiI2C (thanks NooM)



#53900 Help with "structs"

Posted by philvr on 08 November 2013 - 02:28 PM in Visual Studio

I've got the following piece of code public struct MAX6651_DATA { public int nr_fans; public char valid; public uint speed; public uint config; public byte [] tachos = new byte[4]; public uint dac; public uint alarm; } MAX6651_DATA myFan = new MAX6651_DATA(); //create an instance of the fans data structure I would expect... myFan.dac = 100; to assign the dac element the value 100.... Please, what is wrong with this? I must be missing something fundamental! (I fear more background work/reading may be required). Thanks for any advice...



#53899 Code optimisation? Shift left/right instead of divide by 2?

Posted by philvr on 08 November 2013 - 02:21 PM in General Discussion

Thanks for clarifying - Admittedly I don't fully understand the process involved - I'll do some background reading  tonight, promise!




#53896 Code optimisation? Shift left/right instead of divide by 2?

Posted by philvr on 08 November 2013 - 10:40 AM in General Discussion

Is it worth testing the optimisation abilities of the Microsoft Development Environment (Visual Studio) in  greater depth?   If the  Development Environment was originally designed for producing desktop and server based applications could it be that optimisations produced for embedded system code are not what they could be ? What if  the environment had been aimed at producing  embedded code right from the beginning?   We are not talking about producing optimised machine code (are we?) but an intermediate language understood by the CLI. That also raises the question of how the JIT element fits in....   (please correct me if I am wrong)




#53895 Toolbox.NETMF.Hardware.core help?

Posted by philvr on 08 November 2013 - 10:30 AM in Netduino Plus 2 (and Netduino Plus 1)

Agreed that reading all the examples, etc in the forums  really does help to  learn and indeed I have learned a great deal  from other peoples work. I offer a BIG THANK YOU! to all that have contributed code to the forums.

 

But - I never did not find a direct answer to my question...




#53894 Netduino Plus I2C just stops working ?!

Posted by philvr on 08 November 2013 - 10:19 AM in General Discussion

FYI: The i2c issue seems resolved using the latest 4.2 firmware (and I haven't needed to order a Raspberry Pi) :)




#53893 Netduino Plus MK2 Debugging (Deployment) issues when piggybacked onto pcb

Posted by philvr on 08 November 2013 - 10:12 AM in Netduino Plus 2 (and Netduino Plus 1)

FYI Issue resolved! (I'm tidying up loose ends on the board) I think using the latest release of the firmware played a significant part, (also I was mixing up some of the assemblies).



#53892 MCP23017 parallel output operation.

Posted by philvr on 08 November 2013 - 10:10 AM in Netduino Plus 2 (and Netduino Plus 1)

Just a belated "Thanks" to cloris! Your first post was very helpful in getting me started with the MCP23017. We have since modified the paralel i/o routines to use a "write short"  technique that is in line with the 16 pins available on the chip.   We are using the MCP23017 to drive a 10 led bargraph that displays an indication of DC current flow in a battery charge/discharge system...some of the spare lines will drive a piezo sounder and read from a push button switch (but that code has yet to be developed).



#53891 Netduino Plus stops running program shoirtly after attaching USB.

Posted by philvr on 08 November 2013 - 10:05 AM in Netduino Plus 2 (and Netduino Plus 1)

Just a follow up to state that now I have no issues when deploying onto the Netduino Plus MK2 (with the latest production firmware). The software builds and deploys almost immediately every time. :)




#53861 Hall Effect Current Sensors.

Posted by philvr on 07 November 2013 - 02:20 PM in General Discussion

I've been experimenting with a couple of Hall Effect Current Sensors and using them to measure large DC currents (up to 60A). The devices are the CSLA1CD by Honeywell. I've had some success but the device has developed an offset! Out of two units one now produces 5.8V when zero current flows and the other 6.3V! Originally they both produced 6V! My question is has anyone here experience of using Hall Effect Current Sensors? Can they become permanently magnetised if exposed to magnetic fields from associated high current DC cables and hence produce an output that is out of specification? I can not think of any other reason for them to develop an offset but I am new to these devices so am hoping someone reading this can offer advice. regards Philvr



#53047 Code optimisation? Shift left/right instead of divide by 2?

Posted by philvr on 04 October 2013 - 01:52 PM in General Discussion

The i2c MAX6651 fan controller has a tacho count time register that sets a tacho count period 0.25S, 0.5S, 1S or 2S. The tacho counter is read and the time of a fan rotation derived from the counting period set in the tacho count register and the number of pulses counted by the tacho.Questions is this. As the tacho count time register is in powers of 2, is it quicker to use a bitwise shift ( to shift the tacho counter reading right to multiply by two (left to divide by 2) or to use an integer multiply/divide operation?Does anyone know if the clr c# interpreting system would choose the most efficient operation?



#53031 Netduino Plus I2C just stops working ?!

Posted by philvr on 03 October 2013 - 09:31 AM in General Discussion

Interesting, we have a similar issue eith a Netduino PLUS MK2 . One moment all is well and I can obtain data back from I2C, the next the SDA and SCL lines are always at logic "1" and there is no activity. I have a brand new, unused Neduino Plus 2 which I swapped with and the I2C lines both remained high with no clock or data line actions. Next I simply left two 4k7 resistors between SDA,SCL and +3.3V - again no action. This convinces me the additional hardware ( a MAX6651 fan controleler) is ok and there is some issue with the netduino which causes I2C to cease. I am going to order a Raspberry PI as a blind test - to absolutely prove our circuitry is good and the netduino is flaky.



#53002 SDK documentation for the Netduino SDK

Posted by philvr on 30 September 2013 - 09:36 AM in Netduino Plus 2 (and Netduino Plus 1)

An SDK document would be wonderful! I'm currently stuck trying to create a set of I2C transactions, reading through other peoples code helps but does not replace a proper set of documentation.. If a volunteer is required...I would be willing to assist in its creation!



#52734 Toolbox.NETMF.Hardware.core help?

Posted by philvr on 13 September 2013 - 07:43 AM in Netduino Plus 2 (and Netduino Plus 1)

Any ideas? I'm really confused and could very much do with some advice!!

Please can someone explain the purpose of these interfaces? I don’t quite understand how they are intended to be used as there are no direct assignments to the netduinos i/o ports. Is there a tutorial anywhere that demonstrates usage? As an example IParallelOut.cs is reproduced below. I apologise in advance if there is an obvious answer, it is taking me some time to get to grips with c#, I am not a programmer by nature and my brain is having difficulty adapting :( The write must take as an argument some port that has been created elsewhere but how is it created? namespace Toolbox.NETMF.Hardware { /// Generic Purpose Output Array interface public interface IParallelOut : IDisposable { /// Amount of bits in the array uint Size { get; } /// Writes a block of data to the array /// The block of data to write void Write(uint Value); /// Returns the last written block of data /// The last written block of data ] uint Read(); } }




#52703 Mcp 23017 i/o latches and registers

Posted by philvr on 11 September 2013 - 02:47 PM in Project Showcase

Been playing with this chip but it is not behaving quite as I expect. The data sheet states: "Writing to the GPIOn register actually causes a write to the latches (OLATn). Writing to the OLATn register forces the associated output drivers to drive to the level in OLATn" How does this work in practise? Does it matter which port I write to? Is it rude to answer ones own question? I find that if I write zeros to either register I can write the desired output value to the other obtain an output! I haven't discovered what the difference is between the two registers. Perhaps someone can advice?



#52662 Toolbox.NETMF.Hardware.core help?

Posted by philvr on 09 September 2013 - 08:35 AM in Netduino Plus 2 (and Netduino Plus 1)

Please can someone explain the purpose of these interfaces? I don’t quite understand how they are intended to be used as there are no direct assignments to the netduinos i/o ports. Is there a tutorial anywhere that demonstrates usage? As an example IParallelOut.cs is reproduced below. I apologise in advance if there is an obvious answer, it is taking me some time to get to grips with c#, I am not a programmer by nature and my brain is having difficulty adapting :( The write must take as an argument some port that has been created elsewhere but how is it created? namespace Toolbox.NETMF.Hardware { /// Generic Purpose Output Array interface public interface IParallelOut : IDisposable { /// Amount of bits in the array uint Size { get; } /// Writes a block of data to the array /// The block of data to write void Write(uint Value); /// Returns the last written block of data /// The last written block of data ] uint Read(); } }



#52387 MCP23017 parallel output operation.

Posted by philvr on 27 August 2013 - 09:35 AM in Netduino Plus 2 (and Netduino Plus 1)

I'm using the driver code for the mcp23017 from the NET Micro Framework Toolbox but the boolean "inverted" option appears to have no effect. This is set to false in the line data = mux.CreateParallelOut(0, 10,false) But there is no change even when set to "true"/ I am writing to a 10 led bar graph directly from the MCP23017 outputs (the anode of each led is pulled to +3.3v via a resistor). If the inverted boolean option is set to true I expect when I write "0" that the outputs will be inverted (hence at a logic "1") and the leds will remain off. I actually need the inverted option to work. Please, can anyone advice why it is not functioning as expected? namespace mcp23017 { public class Program { static Mcp23017 mux; private static IParallelOut data; public static void Main() { mux = new Mcp23017(32, 100); data = mux.CreateParallelOut(0, 10,false); while (true) { data.Write(0); Thread.Sleep(250); data.Write(1023); Thread.Sleep(250); } } } }



#50874 Netduino Plus 2 Deploy with Debugger

Posted by philvr on 27 June 2013 - 02:07 PM in Netduino Plus 2 (and Netduino Plus 1)

Dave? I've been trying to get deploy though COM1 but I'm not certain I've got the connections right. Please can you confirm which pins you connected to on the NP2 and whether you tied any others high or low? (I assume you used DIO0, DIO1 and ground). Sure I must be doing something silly...(I've downloaded the MFDeploy for serial connections) regards Philvr



#50654 Netduino Plus MK2 Debugging (Deployment) issues when piggybacked onto pcb

Posted by philvr on 20 June 2013 - 10:08 AM in Netduino Plus 2 (and Netduino Plus 1)

When unit is alone I can deploy fine but when I piggyback it onto additional electronics I can not deploy. Consequently I can not debug. Every time I try to debug, Visual C always tries to deploy again and I get a deployment failure. Question 1: Can anyone suggest why I might be unable to deploy when piggybacked onto another pcb? The external circuitry is minimal. It limits the analog and digital voltages to between 0 & 3.3V, it provides 8.6V to the Vin connector and drives a few leds. In theory it ought to be OK...The only worry is that the board will obtain power from Vin while USB is connected for debugging.. Question 2: Are there any alternatives for debugging than USB? Can I use the network, a serial port? or any other type of connection? regards philvr



#50419 Netduino Plus stops running program shoirtly after attaching USB.

Posted by philvr on 11 June 2013 - 09:36 AM in Netduino Plus 2 (and Netduino Plus 1)

Hi Chris. Thanks for your time. If I plug in only via USB the board is fine, if I then add power via Vin the board is still OK. Your answer is excellent news and means my App should be AOK... Regards Philvr



#50347 Netduino Plus stops running program shoirtly after attaching USB.

Posted by philvr on 07 June 2013 - 03:08 PM in Netduino Plus 2 (and Netduino Plus 1)

The Netduino Plus is plugged into an expansion pcb. Vin is provided from an 8.6V regulator via PIN 6 of J6 (the power connector pins). The system boots up and runs some test code when I power on - it simply flashes a bi-colour led via two DIO pins. The 3.3V pin provides power to a SP720 chip used to prevent over voltage on several i/ps. Please can anyone advice if the Netduino is designed to have power attached via J6 AND possibly via USB connection? Looking at the schematic for the Plus MK1 it looks like Q5 should switch the power source between either USB or Vin (via Vprotected)/ Ive been hacking about for some time with the board so I'm wondering if I've blown something. I just need someone to talk this over with so any advice welcome, thanks. Philvr




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