SignalGenerator.Write failed

TinyCLR OS
#1

A strange behavior when the buffer is filled with CopyTo and this is output with SignalGenerator.Write.
The board hangs and only a complete reset with Erase All and so on helps.
When debugging it can be seen that the buffer is filled the same as if I do it with the alternative of transferring every single element …

TimeSpan[] buffer = new TimeSpan[ tapeDataByte.Count ];

/// FAILED with SignalGenerator.Write
/// 
tapeDataByte.CopyTo( buffer );

/// SUCCEEDED with SignalGenerator.Write
///
ushort idx = 0;
foreach( TimeSpan timeSpan in tapeDataByte )
	buffer[ idx++ ] = timeSpan;

tapeWritePin = GpioController.GetDefault().OpenPin( FEZDuino.GpioPin.PD0 );

tapeWriteSignal = new SignalGenerator( tapeWritePin )
{
	DisableInterrupts = false,
	IdleValue = GpioPinValue.Low
};

tapeWriteSignal.Write( buffer );
#2

what type of “tapeDataByte” please?

#3

ArrayList with TimeSpan objects …

double[] time = { 1 / higherTone, 1 / lowerTone };

ushort[] loSig = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1 };
ushort[] hiSig = { 0, 0, 0, 0, 1, 1, 1, 1 };

ArrayList loBit = new();
ArrayList hiBit = new();

foreach( ushort sig in loSig )
{
	loBit.Add( TimeSpan.FromSeconds( time[ sig ] ) );
	loBit.Add( TimeSpan.FromSeconds( time[ sig ] ) );
}

foreach( ushort sig in hiSig )
{
	hiBit.Add( TimeSpan.FromSeconds( time[ sig ] ) );
	hiBit.Add( TimeSpan.FromSeconds( time[ sig ] ) );
}

ArrayList tapeDataByte = new();

tapeDataByte.AddRange( loBit );		// Start bit

byte dataByte = 0xAA;				// Test byte

for( byte i = 0; i < 8; i++ )
{
	byte flag = ( byte )( ( dataByte & ( byte )Math.Pow( 2, i ) ) >> i );

	tapeDataByte.AddRange( ( flag == 1 ) ? hiBit : loBit );
}

tapeDataByte.AddRange( hiBit );		// Stop bit
#4

This is a hobby project to build for a 40 years old Z80 experiment system, which stored the programs on cassette recorder and loaded from it, now so a kind of MemoryTape without changing the system, but the code should not just be sounds, but interpreted to edit them on the PC with a macro assembler.
So, a byte looks and for this your signal generator and SignalCapture are excellent suitable …

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#5

I am not sure this does what you are expecting.

I am not sure exactly what I am saying, but I believe it the issue has to do with references versus objects.

#6

Sorry, but I don’t understand you, what you mean with references. :point_down:
ICollection.CopyTo(Array, Int32) Method (System.Collections) | Microsoft Docs
The copied objects, not their pointers, are in a perfect copied state.
This also in a normal console project.
Only with the application of the method Write of SignalGenerator it bangs …

#7

I investigated your assumption by re-creating the TimeSpan instances before transferring them individually, i.e. simulating a CopyTo:

foreach( TimeSpan timeSpan in tapeDataByte )
	bufferSucceeded[ idx++ ] = new TimeSpan( timeSpan.Ticks );

instead of the previous code :point_down:

foreach( TimeSpan timeSpan in tapeDataByte )
	bufferSucceeded[ idx++ ] = timeSpan;

Both variants work with identically good result …

#8

Unfortunately, the effort to transfer objects from an ArrayList is necessary because the method for SignalGenerator.Write only accepts a native array of TimeSpan structures.
It would be better if there is still an overload for the Write method that also accept objects that implement ICollection …

#9

A mystery.
Both Collections absolutely identical, from all contents, all properties, with identical values … :man_shrugging:

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#10

Can you please provide a simple project that we can reproduce?

If datatype are same, values are same then I don’t see why signal generate different value.
We need full example and value with it. Example 1/2 may not happened but 1/3 may.

#11

My playground: Implicate-X/MemoryTape (github.com)
Above I showed how the pulse sequence looks like with:

SignalGenerator.Write( bufferSucceeded );

And this is what it looks like when

SignalGenerator.Write( bufferFailed );

is called, and then the controller remains frozen … :point_down:

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#12

Instead of CopyTo, I tried the following statement, which again creates a properly filled array, but doesn’t work in the same way.

TimeSpan[] bufferFailed2 = tapeDataByte.ToArray( typeof( TimeSpan ) ) as TimeSpan[];

So, after that again RESET + LDR, Erase all and so on …

#13

Those buffers are different, use for loop for now!

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No need Erase all. there is APP button on FEZ Duino, hold that button, hit reset, release APP button then you can deploy again.

#14

Strange, because above the values 2500 and 5000 are to be seen, only the deep copy probably does not work.
I had tested the three variants in a simple console project under .NET 6 and all work identically.
Is it then probably a deeper problem of TinyCLR?
Well, I have a workaround with the single copying of the array elements … :wink:

#15

We added: ArrayList.Copyto does not work on some DataType fully. · Issue #1163 · ghi-electronics/TinyCLR-Libraries (github.com)

You found a simple workaround, so we are not going to fix this issue for now :)).