Jim,
Official documents like User's Guide or Technical Reference Manual above wiki. Wiki can be modified without any records.
I cannot find SPRUFPOC. I looked up C5515 DSP System User's Guide, SPRUFX5D, on page 28 there are some examples on setting PLL when CLK_SEL=L.
The example in wiki provides a 100MHz when CLK_SEL=L. This isetting should provide a 50MHz.
// program PLL to 50z with CLK_SEL = 0
asm(" *port(#0x1c20) = #0x8BE8 "); //PLL Control 1 reg
asm(" *port(#0x1c21) = #0x8000 "); //PLL Control 2 reg
asm(" *port(#0x1c22) = #0x0806 "); //PLL Control 3 reg
asm(" *port(#0x1C23) = #0x0201; //PLL Control 4 reg
Hope this help.