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TxVpdTx
Description:
- The function issues a virtual port data transmit request for the virtual port identified by cpkey.
Prototype:
- short TxVpdTx (TX_HANDLE handle,
unsigned short datalen,
void *userkey,
unsigned long *cpkey,
TXVPD_DPR_REQ *dprreq );
- handle TX_HANDLE returned from cpi_open.
- datalen Byte length of data in msgdata.
- userkey User-specified key (becomes vpdatchkey).
- cpkey Communications processor-specified key returned on successful attach.
- dprreq Dual port RAM packet to be initialized and issued.
Details
- The transmit function allows an application to pass data frames through the physical resource associated with the virtual port. It is the responsibility of the application to create correctly formatted frames (although certain features like HDLC CRC generation are provided by the CP).
- The data area of the dual port RAM request packet must be set (from msgdata field for datalen) before this function is called. Data is not passed to the API function to avoid a data copy. Refer to Chapter 6 for a description of the data structure used here.
- The maximum data size that can be transmitted is determined by the literal MAXVPDDATA [1438 bytes]. This represents the largest data block that can be transferred over the dual port RAM (MINUS all header information) in a single request.
See Also
- TxVpdAttach, TxVpdEnable
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