5 replies to this topic

[GB30]

Hi! I observed with an oscilloscope the behaviour of this code: static OutputPort out1 = new OutputPort(Pins.GPIO_PIN_D0, false); public static void Main() { while (1==1) { out1.Write(true); out1.Write(false); } } and I measure on pin ton time: it is 60 us. I think that it is a long time for only 2 instructions! if Netduino clock is around 48 MHz, it is a long period Have you got some ideas about it? Thanks!

[Chris Walker]

Hi GB30, Your C# code is running at the managed code layer, so it's being interpreted by the .NET runtime...there is a lot going on behind the scenes. If you'd like to take advantage of the raw speed of the microcontroller, you can write your time-sensitive code in C++ (with a C# wrapper class) and compile it into the Netduino firmware. You can also erase the Netduino and use C/C++ and SAM-BA for a fast 100% native code solution--but that sort of defeats the purpose of having .NET on there. We put the erase pad on the board so that it's fully "hackable." Chris

[GB30]

Hi GB30,

Your C# code is running at the managed code layer, so it's being interpreted by the .NET runtime...there is a lot going on behind the scenes. If you'd like to take advantage of the raw speed of the microcontroller, you can write your time-sensitive code in C++ (with a C# wrapper class) and compile it into the Netduino firmware.

You can also erase the Netduino and use C/C++ and SAM-BA for a fast 100% native code solution--but that sort of defeats the purpose of having .NET on there. We put the erase pad on the board so that it's fully "hackable."

Chris

Thank you for the response. Obviously there is a lot going on behind the scenes.
Is there an example of C# wrapper class?

[CW2]

Is there an example of C# wrapper class?

Please have a look at sweetlilmre's generic BitBanger. What exactly do you want to do?

[BotDuino]

Hi GB30,

Your C# code is running at the managed code layer, so it's being interpreted by the .NET runtime...there is a lot going on behind the scenes. If you'd like to take advantage of the raw speed of the microcontroller, you can write your time-sensitive code in C++ (with a C# wrapper class) and compile it into the Netduino firmware.

You can also erase the Netduino and use C/C++ and SAM-BA for a fast 100% native code solution--but that sort of defeats the purpose of having .NET on there. We put the erase pad on the board so that it's fully "hackable."

Chris

I am trying to write code for my own Software I2C library and need very exacting timing of roughly 30 microseconds. I did the same thing using an oscilloscope, and got about 60 to 70 microseconds. I was wondering if there was a way I could get information on how I could edit/add a library in the firmware to support this.

I opened the firmware, and had no idea where to even begin, any help on this will be greatly appreciated.

[Tom Cerul]

Hi GB30,

Your C# code is running at the managed code layer, so it's being interpreted by the .NET runtime...there is a lot going on behind the scenes. If you'd like to take advantage of the raw speed of the microcontroller, you can write your time-sensitive code in C++ (with a C# wrapper class) and compile it into the Netduino firmware.

You can also erase the Netduino and use C/C++ and SAM-BA for a fast 100% native code solution--but that sort of defeats the purpose of having .NET on there. We put the erase pad on the board so that it's fully "hackable."

Chris

AHA! That would explain the crazy times that I've been seeing!

int a, b, c; b = 2; c = 1;
b++;  // 0 micro seconds (us)
a = b - c;  // 21.4 us !!

long tick = DateTime.Now.Ticks;  // 149.3 us
TimeSpan time = Utility.GetMachineTime(); // 64 us.  NOTE: this is a faster timestamp than getting straight ticks

Good to know that we should only expect 1/1,000th of the performance that the cpu has.