Intel® Core™ Ultra Series 3 Processors I/O Registers
| ID | Date | Version | Classification |
|---|---|---|---|
| 872352 | 04/14/2026 | 001 | Public |
REG SSDR (SSDR) – Offset 10
The Enhanced SSP Data registers are single address locations that Read Write data transfers can access. The SSDR represents two physical registers: the first is temporary storage for data on its way out through the Transmit FIFO, the other is temporary storage for data coming in through the Receive FIFO. As the system accesses the register, FIFO Control logic transfers data automatically between register and FIFO as fast as the system moves it. Data in the FIFO shifts up or down to accommodate the new word (unless its an attempted Write to a full Transmit FIFO). Status bits (such as SSSR.RNE, and SSSR.TNF) show users whether the FIFO is full, above/below a programmable FIFO trigger threshold, or empty. For Transmit data transfers (Write from system to SSP peripheral), the register can be loaded (written) by the system processor anytime it falls below its threshold level when using programmed I/O. When a data size of less than 32-bits is selected, users should not left-justify data written to the Transmit FIFO. Transmit logic left-justifies the data and ignores any unused bits. Received data of less than 32 -bits is automatically right-justified in the Receive FIFO.
| Bit Range | Default | Access | Field Name and Description |
|---|---|---|---|
| 31:0 | 0h | RW | DATA (DATA) Data word to be written to/read from transmit/receive FIFO |