5.36 Set Read Parameters (SRP)
In QPI mode, the Set Read Parameters (C0H) instruction is used to configure both the number of dummy clock cycles and the wrap length for supported high-speed read operations. These include:
- High-Speed Read (0Bh/0Ch) in QPI mode
- 6Bh/6Ch instructions
- 0DH instruction
- EDH/EEH instructions
- 0EH instruction
- 4BH instruction
- 5AH instruction
- Fast Quad I/O Read (EBH/ECH) in QPI mode
- Read Burst with Wrap (0CH) in QPI mode
To initiate the Set Read Parameters instruction in QPI mode, the host asserts CE# low, transmits the SRP command C0H, followed by one byte of Read Parameter data consisting of bits P[7:0], and then deasserts CE# high. Refer to Table 5-14 for the function of the Set Read Parameter bits. Parameter bits P7, P6, P3 and P2 are reserved and not used.
| P5,P4 | Dummy Clocks/ Maximum Frequency (STR) | Dummy Clocks/ Maximum Frequency (DTR) | P1,P0 | Wrap Length (Bytes) |
|---|---|---|---|---|
0,0 | 4 clocks, 80 MHz (Default) | 10 clocks, 108 MHz (Default) | 0,0 | 8 (Default) |
0,1 | 6 clocks, 108 MHz | 4 clocks, 66 MHz | 0,1 | 16 |
1,0 | 8 clocks, 133 MHz | 6 clocks, 80 MHz | 1,0 | 32 |
1,1 | 10 clocks, 166 MHz | 8 clocks, 108 MHz | 1,1 | 64 |