@pepin_vActually i just need to read the temperature data (14 bits), but i have an errors or i still dont know how. sorry im newbie. how can i read just the temp data of max31855? or can you share your vi?
Thank for your really fast answer.
New thread maybe, but I consider it as the same topic - SPI for myRIO. The default personality can read up to 16bits. I think, it is because it uses U16 datatype for read data. But I’m not sure. So my original question (and entreaty) was, if you have your own SPI implementation, where you can set length of the data.
You are right about MAX31855. You can read just 14bits for temperature data, but you need 32bits for all data – thermocouple temperature, cold junction compensation temperature and errors indication (see https://cdn-shop.adafruit.com/datasheets/MAX31855.pdf page 10). And I have problems with reading just 14bits. I have to play with my code more, as I can read data using myRIO default SPI commands but the data read are wrong.
Any advice appreciated because all info I found was for LINX (using Arduino) and nothing for myRIO itself. Some tutorials for FPGA SPI are available, but all are quite complex (=universal) and I haven’t found just simple reader with a various messages lengths.
recently I actually have to come back to MAX31855 :-). A searched online and all you need is to read more frames - two actually (16bit data length) for 32 bits using myRIO I/O Monitor. It worked for me well. And it worked well using myRioSPI RT functions as well. I plan to finish my .vi for reading more MAX31855 simultaneously in about a week. Hopefully.
But you can find bunch of examples online searching for MAX31855 and labview.