Shift Register

Hi @fordav1,

   Thanks for your kind reply.

  The code that makes up the function 'readByte()' that I included, is a 'rearrangement' of the code that makes up the function 'inShift()', that Bill (@dronebot-workshop) used in his sketch, and effectively has the same functionality.

However, inShift() is part of the Arduino library, whilst I explicitly included the coding for readByte(). The Arduino library must also define values for MSBFIRST and LSBFIRST, because they are not defined in 'standard' C or C++. I did not feel comfortable on relying on value definitions that might be changed in the future, albeit the chance of that happening is probably minuscule.

Hence, I converted the function parameter that determines whether the first bit fetched from the shift register was the Least Significant or Most Significant into a kind of question. The code definition for my 'readByte()' function starts:

uint8_t readByte (uint8_t dataPin, uint8_t clockPin, bool isLSBFirst)

The 3rd parameter "bool isLSBFirst", is intended to suggest the implied question, "Is the Least Significant Bit, the first bit fetched from the shift register?", with the argument required to be of the C++ type bool (boolean), which is defined as either true or false. 

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All of which, is a long way of saying, try changing true to false in line 156 of my code, which presently looks like:

byte incoming = readByte(dataIn, clockIn, true);

to

byte incoming = readByte(dataIn, clockIn, false);

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I hope that works.

Best wishes with your project, Dave

@fordav1 I might be missing something, but just swap the wires on the dip sw so that 1 becomes 128 etc.

Hi Ron @zander, 

You are correct, that swapping the wires will do the same job, although that will take longer than replacing true with false in the sketch file.

My explanation is much longer than the one line answer I could have given, because I was also trying to help @fordavi to understand the software, etc., which might be helpful as he builds the test rig into his larger project.

Best wishes, Dave

@davee I didn't look at the sketch, all I heard was the results were backwards so I toook the direct pragmatic route.