I use a commercial version of VS2010 (Visual Studio 2010 Professionnal) and not Visual Studio 2010 Express.

I also use Visual Studio 2010 Professional.

The only code change was the setting of the PWM base clock so this shouldn't be affected.

That's what I thought so I also think it's strange. Could it be something in the upgrade process gone bad?
I followed the instructions from http://wiki.netduino...ep-by-step.ashx and http://wiki.netduino...ep-by-step.ashx
I have .NET MF SDK 4.2 (QFE2) and Netduino SDK v4.2.0 (August 2012) 64-bit installed.
When I execute an application from VS, it deploys correctly but it hangs with the "rebooting" message on the status bar.

aalmada

I upgraded to 4.2.0.1 and the problem got worst. The unplug and plug USB cable doesn't make it work anymore.

Is anyone else experiencing the VS hang with message "The debugging target is not in a initialized state; rebooting..."?

There's a small timing issue with the new PWM classes. We're working on it, and should have an update in about a week.

The issue is fixed with v4.2.0 Update 1 (4.2.0.1)
http://forums.netdui...-v420-update-1/
Thanks Chris!

There's a small timing issue with the new PWM classes. We're working on it, and should have an update in about a week.

Any news on the update?

After that, when I try to debug some code on the Netduino with Visual Studio, it says "The debugging target is not in a initialized state; rebooting..." and nothing more happens.

I started the see the same message after I upgraded to 4.2 firmware.
I found a workaround. Once the message appears, unplug the USB cable on the Netduino side and plug it again. Visual Studio enters debug mode like nothing happened...

aalmada

When I use Microseconds, and use (20000, 1000) in the constructor, the servo would try to move out of the range.

Chris Walker mentions above that there is a "small timing issue with the new PWM classes". I'm waiting for the fix too.

It says that "To enable the servo to move a full 180° use pulse durations of approximately 750 to 2250 μs. Exercise care to not exceed these lower and upper limits.".
What numbers to use in "Microsoft.SPOT.Hardware.PWM(PWMChannels.PWM_PIN_D10, 20000, 1000, PWM.ScaleFactor.Microseconds, false)"? What does 20000 and 1000 mean?

Hi chungenhung,

Servos expect a 20ms second period (20000μs), that's the value you see on the constructor.
To change position you should then change the Duration value. The typical values are from 1000 to 2000, with 1500 for the middle position. In your case, use values from 750 to 2250, 1500 should still be from the middle position.
The constructor requires an initial duration value (that's the 1000 value in the example).

aalmada

Hi,

I was never able to consistently connect to the Wiimote extensions. Now that I upgraded to 4.2 firmware, I'm now trying to use the "repeated start bit" feature.

I tried the following code with the Nunchuck but I'm always getting a buffer full of 0xff values (instead of the expected 0x00, 0x00, 0xa4, 0x20, 0x00, 0x00).

var device = new I2CDevice(new I2CDevice.Configuration(0x52, 400));

device.Execute(new I2CDevice.I2CTransaction[] { 
    CreateWriteTransaction(new byte[] { 0x55, }, 0xf0, 1),
    CreateWriteTransaction(new byte[] { 0x00, }, 0xfb, 1),
}, 1000);
Thread.Sleep(1000);
var buffer = new byte[6];
device.Execute(new I2CDevice.I2CTransaction[] { 
    CreateReadTransaction(buffer, 0xfa, 1),
}, 1000);

This is based on the info from http://wiibrew.org/w...ion_Controllers and using the "repeated start bit" methods from http://forums.netdui...rt-bit-support/

Am I doing it right?

EDIT: I'm using 3.3V for the VCC and 2.2K for pullup resistors.

I created a I2CBus class that fixes many of the I2CDevice issues. It is a singleton, thread-safe and supports repeated start bit.

Source is available at https://bitbucket.or...dware/I2CBus.cs

I hope it will be useful to whoever runs into these issues. Feedback is welcome!

aalmada

For event handlers it's not required. I normally use the NativeEventHandler, for example:

public event NativeEventHandler OnKeyDown;

EventHandler (non-generic version) is to be used on events that don't have any data. It's unfortunate that .NET MF is missing such a basic feature (one line of code).

The use of NativeEventHandler has two issues: It supplies data that is not relevant for my case and it doesn't comply with the .NET design guidelines (chapter 5.4 of Cwalina's book).

aalmada

To use the new I2C InternalAddress feature (repeated start bit) in the v4.1.1 alpha, add the following two methods to your code...and then call them instead of built-in I2CDevice.CreateWriteTransaction/CreateReadTransaction functions when appropriate.

Does this apply to 4.2.0?

Thanks,
aalmada

Hi aalmada,

There's a small timing issue with the new PWM classes. We're working on it, and should have an update in about a week.

Chris

Thanks!

Hi,

I recently upgraded my Netduino to 4.2.0 firmware. I'm now updating my code and I'm having an issue with the new PWM class and servos.

Servos expect a PWM with 20ms period and high signal duration from 1 ms to 2ms. I wrote the following using the new native PWM:

var servo = new Microsoft.SPOT.Hardware.PWM(PWMChannels.PWM_PIN_D10, 20000, 1000, PWM.ScaleFactor.Microseconds, false);
while (true)
{
    Thread.Sleep(1000);
    servo.Duration = 2000; // 2 ms
    Thread.Sleep(1000);
    servo.Duration = 1000; // 1ms
}

And the following using the SecretLabs PWM implementation:

var pwm = new SecretLabs.NETMF.Hardware.PWM(Pins.GPIO_PIN_D10);
uint period = 20000;
while (true)
{
    pwm.SetPulse(period, 1000); // 1 ms
    Thread.Sleep(1000);
    pwm.SetPulse(period, 2000); // 2 ms
    Thread.Sleep(1000);

}

Both examples make the servo move but, it doesn't move 90º and the 2 ms position forces the servo. Am I doing something wrong?

Thanks!

Anxiously awaiting for the final release... Thanks

The "Go-Between Shield" helps you with shield compatibility without having to cut and solder. http://www.sparkfun.com/products/11002

Your effort is valuable, but...why did you create a fixed point math when there is a full-featured set of primitives working very well?
BTW, I'm not sure at all, but the "Single" (float) type should be treated directly from the CPU. Instead, the "Double" is much heavier to treat, and should be avoided in the MF. That's for either performance and memory occupation.
Thanks for sharing, anyway.
Cheers

Having the "full-feature set" doesn't always mean that that's the best performing solution. Just ask the game development people. They usually go out of their way just to save one clock cycle. They are the kind of people that use fixed-point arithmetic: http://netwinder.osu...nw/fix1FAQ.html

I found the following at the TinyCLR forum: "floating point is supported in NETMF, not matter if the processor supports it or not. ARM7 do not have floating point"

I know I should have benchmarked the performance of native types first but I was curious how fixed point works anyway. I was surprised to find that the performance on a Netduino for the multiplication of Int16, Int32, Single or Double, is exactly the same. Unlike you state above, or I'm doing something wrong then...

I found in my recent research that TinyCLR has a native compilation of MathEx for better performance: http://www.tinyclr.c...28/#/1/msg11672

Anyway, it was a great ride and I'm back to my Single-based arithmetic...

aalmada

Hi, I implemented a fixed-point arithmetic class hoping to get some performance boost on my apps. I did some benchmarking on the Netduino and found that it actually slows down considerably. It's a fully managed implementation and that may be the problem. Any feedback is welcome. Here is the code: https://bitbucket.or...ed/Fixed1516.cs aalmada

I find this video tutorial by Jeremy Blum very useful: You can find the full series at http://www.youtube.c...567CE235D39FA84

News from Adafruit... http://player.vimeo.com/video/41452165 EDIT: Adafruit 16-Channel 12-bit PWM/Servo Driver - I2C interface - PCA9685 http://www.adafruit.com/products/815

Great work.
Next week's project will have to be even better!

Thanks!

I was thinking of next controlling this Bionicle with my phone (WP7) through Bluetooth but it's still not possible. I already posted a feedback post at the Windows Phone User Voice. Your vote would be appreciated... ;-)

I could try it using ethernet/wifi but I have the regular Netduino, not the Plus...

aalmada

Here is a video of a little project I implemented last weekend with my kids.

I've created a complete BitConverter for NETMF: https://bitbucket.or...BitConverter.cs It's based on the Utility class as suggested here by Luke but still uses "unsafe" to deal with floats and doubles. I looked into alternatives to the "unsafe", as it's not officially supported, but only found dead ends: 1) [StructLayout(LayoutKind.Explicit)] is supported but [FieldOffset(0)] is not. 2) TypedReference struct is supported but the FieldInfo.SetValueDirect method is not. aalmada

Pololu Micro Serial Servo Controller (assembled) http://www.pololu.co...log/product/207 Pololu RC Servo Controllers http://www.pololu.co...log/category/12

Unions are not available too: if you wish some dirty trick, you'd use the "unsafe" context.

"unsafe" is not officially supported: http://forums.netdui...ndpost__p__2151

Just like baxter, I used the "union" method several times in regular .NET. I tried this approach to avoid the "not-officially supported unsafe" and crashed into the same wall. StructLayoutAttribute is supported but FieldOffsetAttribute is not.

This is plain weird! .NET MF is a subset of .NET but for micro-processors. One of the basic required functionalities in this scenario is serial communication and, there is no official way to marshal floating points and structures... :-/

aalmada