7I76 41
REFERENCE INFORMATION
LBP
LBP is a simple binary master slave protocol where the host sends read, write, or
RPC commands to the 7I76, and the 7I76 responds. All controller communication to the
7I76 is done via LBP. LBP commands always start with a command header byte. This
header specifies whether the command is a read or write or RPC, the number of address
bytes(0, or 2), and the number of data bytes(1 through 8).The 0 address size option
indicates that the current address pointer should be used. This address pointer will be post
incremented by the data size if the auto increment bit is set. RPC commands allow any of
up to 64 stored commands to be executed in response to the single byte command.
Note that the low level serial interface details presented here are not normally
needed for 7I76 card access, as all the low level details are handed by the SSLBP code
in the SSerial interface built into the FPGA, but is presented here for completeness.
LBP DATA READ/WRITE COMMAND
0
1
WR
RID
AI
AS
DS1
DS0
Bit 7.. 6
CommandType: Must be 01b to specify data read/write command
Bit 5
Write: 1 to specify write, 0 to specify read
Bit 4
RPCIncludesData: 0 specifies that data is from stream, 1, that data is from
RPC (RPC only, ignored for non RPC commands)
Bit 3
AutoInc: 0 leaves address unchanged, 1 specifies that address is post
incremented by data size in bytes.
BIT 2
AddressSize: 0 to specify current address, 1 to specify 2 byte address.
Bit 1..0
DataSize: Specifies data size, 00b = 1 bytes, 01b = 2 bytes, 10 b= 4 bytes,
011b = 8 bytes.
When multiple bytes are specified in a read or write command, the bytes are always
written to or read from successive addresses. That is, a 4 byte read at location 0x21 will
read locations 0x21, 0x22, 0x23, 0x24. The address pointer is not modified after the
command unless the AutoInc bit is set.