SPRUHZ7K August 2015 – April 2024 AM5706 , AM5708 , AM5716 , AM5718 , AM5718-HIREL
NOR flash architecture, introduced in 1988, is a flash technology. Unlike NAND, which is a sequential access device, NOR is directly addressable; that is, it is designed to be a random access device. NOR is best suited to devices used to store and run code or firmware, usually in small capacities. While NOR has fast read capabilities, it also has slow write and erase functions when compared to the NAND architecture.
Table 15-307 summarizes the level of the NOR interface signals applied to external devices or memories.
| Bus Operation | CLK | nADV | nCS | nOE | nWE | WAIT | DQ[15:0] |
|---|---|---|---|---|---|---|---|
| Read (asynchronous) | x | L | L | L | H | Asserted | Output |
| Read (synchronous) | Running | L | L | L | H | Driven | Output |
| Read (burst suspend) | Halted | x | L | H | H | Active | Output |
| Write | x | L | L | H | L | Asserted | Input |
| Output disable | x | x | L | H | H | Asserted | High-Z |
| Standby | x | x | H | x | x | High-Z | High-Z |