I am using an LPC4367JET100 on an LPCXpresso4367 to output data using SGPIO. Excluding the rest of my project so that I can solely test the SGPIO, I made a simple program that outputs a 32 bit word of alternating bits (0xAAAAAAAA) continuously over SGPIO in order to allow me to test my outputs using a multi-meter. Since this signal should be equivalent to an average of half the VCC, it should be 1.65v at the pins.
In the code attached below, SGPIO slice B is outputting to SGPIO pin 8 which corresponds to the P1_12 physical pin. On this pin, I get the 1.65v output and I can change it too by using different register values, proving that it works. The problem is the 5 other pins that I need to function do not seem to output this 1.65v (0xAAAAAAAA). The documentation for SGPIO is very confusing but I believe this is how the pins are muxed internally for 1 bit mode:
SGPIO slice B -> SGPIO pin 8 -> physical pin P1_12 (SCU function 6 this one works but none of the others seem to)
SGPIO slice L -> SGPIO pin 7 -> physical pin P2_6 (SCU function 0)
SGPIO slice M -> SGPIO pin 9 -> physical pin P1_13 (SCU function 6)
SGPIO slice N -> SGPIO pin 11 -> physical pin P1_4 (SCU function 2)
SGPIO slice O -> SGPIO pin 13 -> physical pin P2_4 (SCU function 0)
SGPIO slice F -> SGPIO pin 6 -> physical pin P2_2 (SCU function 0)
Please correct me if I am wrong on understanding how the SGPIO slices mux internally. P1_13 is a specific one which did not work where I tried switching the SCU pin function to every possible value and on none did I get any 1.65v output. I also decided to check all the pins available to me on the board in case I was checking the wrong pins but no other pins had this 1.65v /were controllable via SGPIO slice.
Thank you for looking into this.