Editing Nios II (section)

== Nios II CPU family ==
Nios II classic is offered in 3 different configurations: Nios II/f (fast), Nios II/s (standard), and Nios II/e (economy).
Nios II gen2 is offered in 2 different configurations: Nios II/f (fast), and Nios II/e (economy).

=== Nios II/f ===
The Nios II/f core is designed for maximum performance at the expense of core size. Features of Nios II/f include:
* Separate instruction and data caches (512&nbsp;[[byte|B]] to 64&nbsp;[[kilobyte|KB]])
* Optional [[memory management unit|MMU]] or [[Memory protection unit|MPU]]
* Access to up to 2&nbsp;[[gigabyte|GB]] of external address space
* Optional tightly coupled memory for instructions and data
* Six-stage pipeline to achieve maximum [[DMIPS]]/MHz
* Single-cycle hardware multiply and barrel shifter
* Optional hardware divide option
* Dynamic [[branch predictor|branch prediction]]
* Up to 256 custom instructions and unlimited hardware accelerators
* [[JTAG]] debug module
* Optional JTAG debug module enhancements, including hardware breakpoints, data triggers, and real-time trace

=== Nios II/s ===
Nios II/s core is designed to maintain a balance between performance and cost. This core implementation is not longer supported for Altera Quartus II v.17 and newer. Features of Nios II/s include:
* Instruction cache
* Up to 2&nbsp;GB of external address space
* Optional tightly coupled memory for instructions
* Five-stage pipeline
* Static branch prediction
* Hardware multiply, divide, and shift options
* Up to 256 custom instructions
* [[JTAG]] debug module
* Optional JTAG debug module enhancements, including hardware breakpoints, data triggers, and real-time trace

=== Nios II/e ===
The Nios II/e core is designed for smallest possible logic utilization of FPGAs. This is especially efficient for low-cost Cyclone II FPGA applications. Features of Nios II/e include:
* Up to 2&nbsp;GB of external address space
* [[JTAG]] debug module
* Complete systems in fewer than 700&nbsp;[[Logic block#Architecture|LE]]s
* Optional debug enhancements
* Up to 256 custom instructions
* Free, no license required