I'm using a Mega and the TLC5940 library by AC (Arduino Tlc5940 Library: Tlc5940 Class Reference). The library works great.
The library does not include the ability to read the status information output from Sout. I'd really like to know about open LEDs (LOD) and thermal shutdowns (TEF) through the serial port (this information is available for shifting out of Sout after an XLAT latch). The hardware pin doesn't give the full detail, so I want this information from Sout.
I assume this would involve shifting in a bunch of dummy (or duplicate) data after XLAT and reading the stream in through the MISO SPI port. Beyond that, I have no idea how to implement this in the library.
I've not done any library development before, so I fear this may be a bit out of my league. I'd really appreciate any advice, code snippets or words of warning on this. Any thoughts? Has anyone tried this already?
See page 13 of the datasheet:
"To differentiate LOD and TEF signal from XERR pin, LOD can be masked out with BLANK = HIGH."
If XERR is LOW, indicating an error, you can set BLANK to HIGH.
If XERR remains LOW the problem is TEF (Thermal Error Flag).
If XERR goes HIGH the problem is LOD (LED Open Detection).
Thanks for the reply.
I'm planning on using many TLC5940s in series and would like to know every detail of the error, namely which one is in thermal shutdown (TEF) and which LED on which driver is open (LOD) without using dozens of digital input pins (I guess a big mux is an option here, but it's definitely not ideal). All of this information and the dot correction values are available on Sout, called the status information data (SID). The transfer is documented on page 18 of the datasheet.
Neither the TLC5940 nor any of the other libraries or code I've found has implemented this feature, so I'm wondering if anyone has any experience with it.