pio-usb now only need sysclk to be multiple of 12Mhz

Author: hathach

hw/bsp/rp2040/boards/raspberry_pi_pico/board.cmake

@@ -1,2 +1,3 @@
 set(PICO_PLATFORM rp2040)
 set(PICO_BOARD pico)
+#set(OPENOCD_SERIAL E6614103E719612F)

hw/bsp/rp2040/family.c

@@ -162,8 +162,12 @@ void stdio_rtt_init(void) {
 void board_init(void)
 {
 #if (CFG_TUH_ENABLED && CFG_TUH_RPI_PIO_USB) || (CFG_TUD_ENABLED && CFG_TUD_RPI_PIO_USB)
-  // Set the system clock to a multiple of 120mhz for bitbanging USB with pico-usb
+  // Set the system clock to a multiple of 12mhz for bit-banging USB with pico-usb
   set_sys_clock_khz(120000, true);
+  // set_sys_clock_khz(180000, true);
+  // set_sys_clock_khz(192000, true);
+  // set_sys_clock_khz(240000, true);
+  // set_sys_clock_khz(264000, true);
 
 #ifdef PICO_DEFAULT_PIO_USB_VBUSEN_PIN
   gpio_init(PICO_DEFAULT_PIO_USB_VBUSEN_PIN);