I use two channels upp and one hi-speed USB device port at the same time and It works well on my board.
But the upp frequency is 48MHz (ddr mode), higher than recommened 37.5MHz (ddr mode).
The core frequency is 384MHz.
upp-ch-a : output 16bit * 48MHz * 2 (ddr mode) from 128KB sram
upp-ch-b : input 16bit * 24MHz *2 (ddr mode)
USB: send data to a PC HOST, the data rate is about 25~30MB/s.
So, is 48MHz ok? It works well whatever.