add example description

Author: hathach

examples/CDC/cdc_multi/cdc_multi.ino

@@ -7,15 +7,17 @@
     MIT license, check LICENSE for more information
 */
 
-/* The example creates two virtual serial ports. Text entered on
-   any of the ports will be echoed to the all ports with
-   - all lower case in port0 (Serial)
-   - all upper case in port1
 
-   The max number of CDC ports (CFG_TUD_CDC) has to be changed to at least 2.
-   Config file is located in Adafruit_TinyUSB_Arduino/src/arduino/ports/platform/tusb_config_platform.h
-   where platform is one of: esp32, nrf, rp2040, samd
-*/
+/* The example creates two virtual serial ports. Text entered on
+ * any of the ports will be echoed to the all ports with
+ *  - all lower case in port0 (Serial)
+ *  - all upper case in port1
+ *
+ * Requirement:
+ *  The max number of CDC ports (CFG_TUD_CDC) has to be changed to at least 2.
+ *  Config file is located in Adafruit_TinyUSB_Arduino/src/arduino/ports/platform/tusb_config_platform.h
+ *  where platform is one of: esp32, nrf, rp2040, samd
+ */
 
 #include <Adafruit_TinyUSB.h>
 

examples/DualRole/device_info_rp2040/device_info_rp2040.ino

@@ -9,6 +9,37 @@
  any redistribution
 *********************************************************************/
 
+
+/* This example demonstrates use of both device and host, where
+ * - Device run on native usb controller (controller0)
+ * - Host run on bit-banging 2 GPIOs with the help of Pico-PIO-USB library (controller1)
+ *
+ * Requirements:
+ * - [Pico-PIO-USB](https://github.com/sekigon-gonnoc/Pico-PIO-USB) library
+ * - 2 consecutive GPIOs: D+ is defined by HOST_PIN_DP (gpio2), D- = D+ +1 (gpio3)
+ * - Provide VBus (5v) and GND for peripheral
+ *
+ * RP2040 host stack will get device descriptors of attached devices and print it out via
+ * device cdc (Serial) as follows:
+ *    Device 1: ID 046d:c52f
+      Device Descriptor:
+        bLength             18
+        bDescriptorType     1
+        bcdUSB              0200
+        bDeviceClass        0
+        bDeviceSubClass     0
+        bDeviceProtocol     0
+        bMaxPacketSize0     8
+        idVendor            0x046d
+        idProduct           0xc52f
+        bcdDevice           2200
+        iManufacturer       1     Logitech
+        iProduct            2     USB Receiver
+        iSerialNumber       0
+        bNumConfigurations  1
+ *
+ */
+
 // pio-usb is required for rp2040 host
 #include "pio_usb.h"
 #define HOST_PIN_DP   2   // Pin used as D+ for host, D- = D+ + 1