VxWorks Reference Manual : Libraries
wdbSlipPktDrv - a serial line packetizer for the WDB agent
wdbSlipPktDevInit( ) - initialize a SLIP packet device for a WDB agent
This is a lightweight SLIP driver that interfaces with the WDB agents UDP/IP interpreter. It is the lightweight equivalent of the VxWorks SLIP netif driver, and uses the same protocol to assemble serial characters into IP datagrams (namely the SLIP protocol). SLIP is a simple protocol that uses four token characters to delimit each packet:
- FRAME_END (0300)
- FRAME_ESC (0333)
- FRAME_TRANS_END (0334)
- FRAME_TRANS_ESC (0335)The END character denotes the end of an IP packet. The ESC character is used with TRANS_END and TRANS_ESC to circumvent potential occurrences of END or ESC within a packet. If the END character is to be embedded, SLIP sends "ESC TRANS_END" to avoid confusion between a SLIP-specific END and actual data whose value is END. If the ESC character is to be embedded, then SLIP sends "ESC TRANS_ESC" to avoid confusion. (Note that the SLIP ESC is not the same as the ASCII ESC.)
On the receiving side of the connection, SLIP uses the opposite actions to decode the SLIP packets. Whenever an END character is received, SLIP assumes a full packet has been received and sends on.
This driver has an MTU of 1006 bytes. If the host is using a real SLIP driver with a smaller MTU, then you will need to lower the definition of WDB_MTU in configAll.h so that the host and target MTU match. If you are not using a SLIP driver on the host, but instead are using the target server's wdbserial backend to connect to the agent, then you do not need to worry about incompatabilities between the host and target MTUs.
wdbSlipPktDevInit( ) - initialize a SLIP packet device for a WDB agent
void wdbSlipPktDevInit ( WDB_SLIP_PKT_DEV * pPktDev, /* SLIP packetizer device */ SIO_CHAN * pSioChan, /* underlying serial channel */ void (* stackRcv)() /* callback when a packet arrives */ )
This routine initializes a SLIP packet device on one of the BSP's serial channels. It is typically called from usrWdb.c when the WDB agent's lightweight SLIP communication path is selected.
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