AndesCore™ N25F Overview
- AndeStar™ V5 Instruction Set Architecture (ISA), compliant to RISC-V technology
- Floating point extensions
- Bit-manipulation extensions
- Andes extensions, architected for performance and functionality enhancements
- Separately licensable Andes Custom Extension™ (ACE) for customized acceleration
- 32-bit, 5-stage pipeline CPU architecture
- 16/32-bit mixable instruction format for compacting code density
- Branch prediction to speed up control code
- Return Address Stack (RAS) to speed up procedure returns
- Physical Memory Protection (PMP)
- Flexibly configurable Platform-Level Interrupt Controller (PLIC) for supporting wide range of system event scenarios
- Enhancement of vectored interrupt handling for real-time performance
- Advanced CoDense™ technology to reduce program code size
AndesCore™ N25F is a 32-bit CPU IP core based on AndeStar™ V5 architecture which incorporated RISC-V technology, it is capable of delivering high per-MHz performance and operating at high frequencies, at the same time it is small in gate count. N25F also supports single- and double-precision floating point and bit-manipulation instructions. N25F comes with options, including branch prediction for efficient branch execution, Instruction and Data caches, Local Memories for low-latency accesses, ECC for L1 memory soft error protection, and Andes Custom Extension™ (ACE) to add proprietary instructions to accelerate performance/power consumption critical spots.
N25F’s 5-stage pipeline is optimized for high operating frequency and high performance. Features also includes PLIC and vectored interrupts for serving various types of system events, AXI 64-bit or AHB 64/32-bit bus, PowerBrake, QuickNap™ and WFI mode for low power and power management, and JTAG debug interface for development support
Development Tools
- AndeSight™ Integrated Development Environment
- COPILOT: Custom-OPtimized Instruction deveLOpment Tool for ACE
- ICE debugging hardware
Key Features and Performance
AndeStar™ V5 Architecture
Key Features | Benefits |
---|---|
RISC-V RV32IMACFDB Instructions |
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RISC-V single and double precision floating point instruction | Accelerate the processing of high precision arithmetic |
RISC-V bit-manipulation instructions, including the Zba, Zbb, Zbc and Zbs extensions | Benefits codes with bit-wise operations |
Andes Extended Instructions | Andes exclusive performance and functionality enhancements |
Andes Custom Extension™ (ACE) option to create customized instructions for software acceleration |
|
16/32-bit mixable instruction format | For compact code density |
32 general-purpose registers | For better code size and performance |
Machine (M) and User (U) Privilege levels | Embedded systems with privilege protections |
CPU Core
Key Features | Benefits |
---|---|
3.57 Coremark/MHz, 1.98 DMIPS/MHz* | Superior performance-per-MHz |
5-stage pipeline, with a full-cycle reserved for critical SRAM accesses | Superior performance-efficiency, while allowing for high speeds |
Extensive branch prediction features
|
|
Physical Memory Protection (PMP), 16 regions | Basic read/write/execute memory protection with minimum cost |
Performance monitors | Program code performance tuning |
StackSafe™ hardware stack protection |
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Multiplier options
| Option to choose between speed and area according to application's requirements |
PowerBrake technology | Performance throttling to digitally reduce power consumption |
QuickNap™ technology | Fast power-down/wake-up support for caches |
* AndeSight v500, DMIPS/MHZ follow Dhrystone’s no-inline ground rules, best performances
Memory Subsystems
Key Features | Benefits |
---|---|
I-Cache & D-Cache
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ILM & DLM
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Soft-error protection: ECC or parity for I-Cache and D-Cache, ILM and DLM with SRAM interface | Code and data integrity protection |
Bus manager port: AXI with 64-bit data or AHB with 64 or 32-bit data, AXI with I/D separate or joint bus | User-selectable bus interface for optimal efficiency |
Bus subordinate port: AHB with 64 or 32-bit data, for ILM/DLM accesses | Efficient data transfer between CPU and SoC managers |
Core/bus clock ratio of N:1 | Simplified SoC integration |
Platform-Level Interrupt Controller (PLIC)
Key Features | Benefits |
---|---|
Implements RISC-V PLIC specification
| Allow individual interrupts to be serviced and prioritized without sharing |
Enhanced interrupt features
|
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Debug Support
Key Features | Benefits |
---|---|
Implements RISC-V debug specifications | Supported by industry debug tool suppliers |
JTAG Debug Port | Industry-standard support |
Embedded Debug Module with up to 8 triggers | Flexible configurations to tradeoff between gate count and debugging capabilities |
Exception redirection support | Entering debugger upon selected exceptions without using breakpoints |
Performance
Core, Process | N25F (w/o FPU), 28HPC+ |
---|---|
Frequency (MHz) | 50 |
Dynamic power (uW/MHz) | 3.6 |
Area (mm2) | 0.032 |
Core, Process | N25F (w/o FPU), 28HPC+ | N25F (with FPU), 28HPC+ |
---|---|---|
Frequency (MHz) | 1000 | 1000 |
Dynamic power (uW/MHz) | 4.1 | 6.6 |
Area (mm2) | 0.033 | 0.089 |
* Base configuration, SVT 9-track library, SS corner, 0.81V, -40°C, and with I/O constraint. Power consumption at TT corner, 0.9V, 25°C
Product Package
N25F with CPU Subsystem
- Pre-integrated N25F, PLIC, Debug Module and simulation-only encrypted Platform
N25F with AE350 Platform
- N25F with CPU Subsystem, plus AXI/AHB Platform