add low power

lib_xud/lib_xud/src/core/XUD_Main.xc

@@ -393,16 +393,18 @@ static int XUD_Manager_loop(XUD_chan epChans0[], XUD_chan epAddr_Ready[],  chane
             }
 
             XUD_HAL_Mode_DataTransfer();
-
+#ifndef LOW_POWER_EN
             set_thread_fast_mode_on();
+#endif
 
             /* Run main IO loop */
             /* flag0: Rx Error
                flag1: Rx Active
                flag2: Null / Valid Token  */
             noExit = XUD_LLD_IoLoop(p_usb_rxd, flag1_port, p_usb_txd, flag0_port, flag2_port, epTypeTableOut, epTypeTableIn, epAddr_Ready, noEpOut, c_sof);
-
+#ifndef LOW_POWER_EN
             set_thread_fast_mode_off();
+#endif
 
             if(!noExit)
                 break;

sw_usb_audio/app_usb_aud_fosi_c1/src/extensions/power_down.xc

@@ -0,0 +1,24 @@
+#include <platform.h>
+
+void power_down()
+{
+#if (LOW_POWER_EN == 1)
+    // Give the software 10 seconds to start up, then apply power optimisations below.
+    timer tmr;
+    int t;
+    tmr :> t;
+    tmr when timerafter(t+1000000000) :> void;
+
+    // Reduce switch clock frequency
+//    write_node_config_reg(tile[0], XS1_SSWITCH_CLK_DIVIDER_NUM, 4);
+    write_node_config_reg(tile[1], XS1_SSWITCH_CLK_DIVIDER_NUM, 4);
+//
+//	// Reduce core 0 clock frequency (to 9 MHz)
+//    // Note, to completely disable, use:
+//    // write_tile_config_reg(tile[0], XS1_PSWITCH_PLL_CLK_DIVIDER_NUM, 0x80000000);
+//    write_tile_config_reg(tile[0], XS1_PSWITCH_PLL_CLK_DIVIDER_NUM, 0x00000040);
+    write_tile_config_reg(tile[1], XS1_PSWITCH_PLL_CLK_DIVIDER_NUM, 0x00000040);
+
+    setps(XS1_PS_XCORE_CTRL0, 0x10);
+#endif
+}