Fix issue stm32duino#478.

ghent360 · fpistm · commit d8a5df7be11f · 2019-03-25T16:23:51.000+01:00
diff --git a/cores/arduino/stm32/usb/cdc/usbd_cdc_if.c b/cores/arduino/stm32/usb/cdc/usbd_cdc_if.c
@@ -263,8 +263,9 @@ void CDC_deInit(void)
 
 bool CDC_connected()
 {
-  uint32_t transmitTime = 0;
-  if (transmitStart) {
+  // Save the transmitStart value in a local variable - fix #478
+  uint32_t transmitTime = transmitStart;
+  if (transmitTime) {
     transmitTime = HAL_GetTick() - transmitStart;
   }
   return hUSBD_Device_CDC.dev_state == USBD_STATE_CONFIGURED

Original file line number	Diff line number	Diff line change
`@@ -263,8 +263,9 @@ void CDC_deInit(void)`
`263`	`263`
`264`	`264`	`bool CDC_connected()`
`265`	`265`	`{`
`266`		`- uint32_t transmitTime = 0;`
`267`		`- if (transmitStart) {`
	`266`	`+ // Save the transmitStart value in a local variable - fix #478`
	`267`	`+ uint32_t transmitTime = transmitStart;`
	`268`	`+ if (transmitTime) {`
`268`	`269`	`transmitTime = HAL_GetTick() - transmitStart;`
`269`	`270`	`}`
`270`	`271`	`return hUSBD_Device_CDC.dev_state == USBD_STATE_CONFIGURED`