STCS - Store Data to Control and Status Register Space

The STCS instruction is used to store data to the UPDI Control and Status register space. Data are shifted in serially into the PHY layer shift register and written as a whole byte to a selected CS register. The STCS instruction is based on direct addressing, where the address is part of the instruction operand. The STCS instruction can access only the internal UPDI register space. This instruction supports only byte access, and the data size is not configurable.

Figure 1. STCS Instruction Operation

Figure 1 shows the data frame transmitted after the SYNCH character and the instruction frames. The STCS instruction byte can be immediately followed by the data byte. There is no response generated from the STCS instruction, as is the case for the ST and STS instructions.