33.3.3.1 LDS
- Load Data from Data
Space Using Direct Addressing
The LDS
instruction is used to load data form the bus matrix and
into the serial shift register for serial read out. The LDS
instruction
is based on direct addressing, and the address must be given as an operand to the
instruction for the data transfer to start. Maximum supported size for address and data
is 16 bit. LDS
supports repeated memory access when combined with the
REPEAT
instruction.
As shown in Figure 33-9, after issuing the SYNCH character followed by the LDS instruction,
the number of desired address bytes, as indicated by the SizeA field in the instruction,
must be transmitted. The output data size is selected by the SizeB field, and is issued
after the specified Guard Time. When combined with the REPEAT
instruction, the address must be sent in for each iteration of the repeat, meaning after
each time the output data sampling is done. There is no automatic address increment when
using REPEAT
with LDS
, as it uses a direct addressing
protocol.
LDS
Instruction
Operation