ST
- Store Data from Data Space Using Indirect
AddressingThe ST
instruction is used to store data that is shifted serially
into the PHY layer to the bus matrix address space. The ST
instruction
is based on indirect addressing, which means that the Address Pointer in the UPDI needs
to be written prior to bus matrix access. Automatic pointer post-increment operation is
supported, and is useful when the ST
instruction is used with
REPEAT
. ST
is also used to store the UPDI Address
Pointer into the Pointer register. The maximum supported size for storing address and
data is 16 bits.
ST
Instruction
Operation
ST
to the UPDI Pointer register and store of regular data. In both
cases, an Acknowledge (ACK) is returned by the UPDI if the store was
successful and a SYNCH character is sent before each instruction. To
write the UPDI Pointer register, the following procedure should be
followed:ST
instruction to the
signature 0x2ST
instruction, send Size A bytes of
address dataST
instruction to the
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 executedST
instruction, send Size B bytes of
address dataWhen used with the REPEAT
, 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 REPEAT
, the data frame of Size B data bytes can be sent
after each received ACK.