Part Number: BEAGLEBN
Tool/software: Linux
Hi,
I'm reading the ads8860 with the PRU0 of the Beaglebone Black Rev C, and the PRU1 is doing a timer to get a 500kHz sampling rate, so i adapt the code from the Derek Moloy example(exploringbeaglebone.com/.../ ) to the mcp3008, to this ADC(ads8860), but i'm getting to many samples with erros.
After many tests i discover the problem, for example when i have a constant voltage in analog input, like 3,3 V i should receive 43253(16 bits resolution with Vref=5V) or something close to that on all samples, but i have many samples with 43261, 43317, 43512, ... all this error samples are +8,+16,+24,+32,...+256 or -256 than the original value. So my conclusion is my software is shifting or losing the less significant bits of the samples, and after the first error, the percentage of error start growing. I did the same communication in a 23k256 memory(SPI), and reading an adress where is the value(15-1111), the software reads many 14(1110) and 12(1100).
There is the PRUADC.p and the PRUClock.p and PRUADC.c for the communication with the ads8860.
Any help would be aprecciated, and if you want more informations about this, please say.
Best Regards,
David
