Merge pull request #7090 from jorisa/usbserial-write-nonblocking

Add non-blocking write function for USBCDC

Author: Cruz Monrreal

features/unsupported/USBDevice/USBSerial/USBCDC.cpp

@@ -127,6 +127,10 @@ bool USBCDC::send(uint8_t * buffer, uint32_t size) {
     return USBDevice::write(EPBULK_IN, buffer, size, MAX_CDC_REPORT_SIZE);
 }
 
+bool USBCDC::send_NB(uint8_t * buffer, uint32_t size) {
+    return USBDevice::writeNB(EPBULK_IN, buffer, size, MAX_CDC_REPORT_SIZE);
+}
+
 bool USBCDC::readEP(uint8_t * buffer, uint32_t * size) {
     if (!USBDevice::readEP(EPBULK_OUT, buffer, size, MAX_CDC_REPORT_SIZE))
         return false;

features/unsupported/USBDevice/USBSerial/USBCDC.h

@@ -70,7 +70,7 @@ class USBCDC: public USBDevice {
     virtual const uint8_t * configurationDesc();
 
     /*
-    * Send a buffer
+    * Send a buffer. Warning: blocking
     *
     * @param endpoint endpoint which will be sent the buffer
     * @param buffer buffer to be sent
@@ -79,6 +79,16 @@ class USBCDC: public USBDevice {
     */
     bool send(uint8_t * buffer, uint32_t size);
 
+    /*
+    * Send a buffer. Warning: non blocking
+    *
+    * @param endpoint endpoint which will be sent the buffer
+    * @param buffer buffer to be sent
+    * @param size length of the buffer
+    * @returns true if successful
+    */
+    bool send_NB(uint8_t * buffer, uint32_t size);
+
     /*
     * Read a buffer from a certain endpoint. Warning: blocking
     *