TMS320F28388D: How to output ESC SYNC0 signal through a GPIO?

Hi expert,

    At the ESC peripheral,I cannot understand the filed SYNC0_IOPAD_SEL in register ESCSS_SYNC_IO_CONFIG . I need to output my SYNC0 singal through a GPIO(ex.GPIO127),how should I set the SYNC0_IOPAD_SEL bits?I'm now using the example projects fcl_f2838x_tmdxiddk_cpu1 and f2838x_cm_cia402_solution.

    thanks.