stmhal: Add USB_VCP class/object, for direct USB VCP control.

Before, pyb.stdin/pyb.stdout allowed some kind of access to the USB VCP
device, but it was basic access.

This patch adds a proper USB_VCP class and object with much more control
over the USB VCP device.  Create an object with pyb.USB_VCP(), then use
this object as if it were a UART object.  It has send, recv, read,
write, and other methods.  send and recv allow a timeout to be specified.

Addresses issue 774.

1 files changed, 7 insertions, 4 deletions

diff --git a/stmhal/usbd_cdc_interface.h b/stmhal/usbd_cdc_interface.h
index c1fa54020..f312682fb 100644
--- a/stmhal/usbd_cdc_interface.h
+++ b/stmhal/usbd_cdc_interface.h
@@ -20,8 +20,8 @@
   *

   *        http://www.st.com/software_license_agreement_liberty_v2

   *

-  * Unless required by applicable law or agreed to in writing, software 

-  * distributed under the License is distributed on an "AS IS" BASIS, 

+  * Unless required by applicable law or agreed to in writing, software

+  * distributed under the License is distributed on an "AS IS" BASIS,

   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

   * See the License for the specific language governing permissions and

   * limitations under the License.

@@ -36,6 +36,9 @@ void USBD_CDC_HAL_TIM_PeriodElapsedCallback(void);
 

 int USBD_CDC_IsConnected(void);

 void USBD_CDC_SetInterrupt(int chr, void *data);

-void USBD_CDC_Tx(const char *str, uint32_t len);

+

+int USBD_CDC_Tx(const uint8_t *buf, uint32_t len, uint32_t timeout);

+void USBD_CDC_TxAlways(const uint8_t *buf, uint32_t len);

+

 int USBD_CDC_RxNum(void);

-int USBD_CDC_RxGet(void);

+int USBD_CDC_Rx(uint8_t *buf, uint32_t len, uint32_t timeout);