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REFERENCE INFORMATION
SSERIAL REMOTE RPCS
SSerial remote devices must implement three special RPCs to be compatible with
the hosts FPGA SSLBP firmware. These RPCs may be normal in-memory RPCs or
special hardwired RPCs for speed. Normal programmable RPCs are not required for
compatibility with SSLBP so need not be implemented.
UNIT NUMBER RPC
The unit number RPC returns the 4 byte remote unit number. Like all LBP data this
is sent LSB first. This RPC is 0xBB hex.
DISCOVERY RPC
The discovery RPC returns the total sizes of the receive and transmit process data
in bytes and returns 16 bit pointers to the PTOC and GTOC (which are in turn tables of
pointers to process data records and mode records). The discovery RPC is 0xBC hex.
Return data bytes are in the following order: RXSize, TXSize, PTOCLSB,
PTOCMSB, GTOCLSB, GTOCMSB.
RXSize is host relative so this is the size of data that the remote transmits. Likewise
TXSize is host relative so this is the size of process data the remote receives. Note that
the remote should check its remote SW mode and remote HW mode flags and return size
data and pointers appropriate for the currently selected mode. Note that the remote always
sends remote fault data as the first byte of the process data sent to the host. This extra
byte of data must be reflected in the RXSize byte.
PROCESS DATA RPC
The Process data RPC is used to transfer process data to and from the host. The
process data RPC should always receive and send the amount of RX and TX data that the
Discovery RPC indicates. As mentioned above, the first byte of data sent from the remote
to the host is always remote fault information as listed in CS REGISTER AFTER DOIT
section of the manual. The process data RPC is 0xBD hex.