ST
- Store Data from UPDI to
Data Space Using Indirect AddressingThe ST
instruction is used to store data from the UPDI PHY shift
register to the data space. The ST
instruction is used to store data
that are shifted serially into the PHY layer. The ST
instruction is
based on indirect addressing, which means that the Address Pointer in the UPDI needs to
be written before the data space. The automatic pointer post-increment operation is
supported and is useful when the ST
instruction is utilized with the
REPEAT
instruction. The ST
instruction is also
used to store the UPDI Address Pointer into the Pointer register. The maximum supported
size for storing address and data is 32 bits.
ST
Instruction
OperationThe figure above gives an example of an ST
instruction to
the UPDI Pointer register and the storage of regular data. A SYNCH character is sent
before each instruction. In both cases, an Acknowledge (ACK) is sent back by the UPDI if
the ST
instruction was successful.
ST
instruction to signature 0x2
.ST
instruction, send Size A bytes of address data.ST
instruction to signature 0x0
to write
to the address specified by the UPDI Pointer register. If the PTR field is set
to 0x1
, the UPDI pointer is automatically updated to the next
address according to the data size Size B field of the instruction after the
write is executed.ST
instruction, send Size B bytes of data.When used with the REPEAT
instruction, it is recommended to
set up the Address register with the start address for the block to be written and use
the Pointer Post Increment register to automatically increase the address for each
repeat cycle. When using the REPEAT
instruction, the data frame of Size
B data bytes can be sent after each received ACK.