Silicon Laboratories SiM3U1xx Manual de usuario descargar pdf (Pagina 4)

AN758

4 Rev. 0.1

3.2. Class Notifications

Table 4 shows the class notifications supported by the Abstract Control Model.

3.2.1. Serial State

This notification sends an asynchronous message containing the current UART status.

The data field for this notification is a bitmapped value that contains the current state of detects transmission

carrier, break, ring signal, and device overrun error. These signals are typically found on a UART and are used for

communication status reporting. A state is considered enabled if its respective bit is set to 1.

Note: The firmware example included with this application does not currently support state change.

Table 4. Abstract Control Model Notifications

Notification Code Description

SERIAL_STATE 20h Returns the current state of the carrier detects, DSR,

break, and ring signal.

bmRequestType bRequest wValue wIndex wLength Data

10100001b SERIAL_STATE 0 interface 2 UART state

bitmap

Table 5. UART State Bitmap

Bit Position Field Description

15:7 Reserved (future use).

6 bOverRun Received data has been discarded due to overrun in the device.

5 bParity A parity error occurred.

4 bFraming A framing error occurred.

3 bRingSignal State of ring signal detection of the device.

2 bBreak State of break detection mechanism of the device.

1 bTxCarrier State of transmission carrier. This signal corresponds to V.24 signal 106 and

RS232 signal DSR.

0 bRxCarrier State of receiver carrier detection mechanism of device. This signal corresponds

to V.24 signal 109 and RS232 signal DCD.

1 2 3 4 5 6 7 8 9 ... 29 30

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Silicon Laboratories SiM3U1xx Manual de usuario Pagina 4