AndesCore™ A25 Overview
- AndeStar™ V5 Instruction Set Architecture (ISA), compliant to RISC-V technology
- Floating point 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 predication to speed up control code
- Return Address Stack (RAS) to speed up procedure returns
- Memory Management Unit (MMU) and 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™ A25 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. A25 also supports single and double precision floating point instructions, and MMU for Linux based applications. A25 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.
A25’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 and WFI mode for low power and power management, and JTAG debug interface for development support.
Applications
- Networking and Communications
- Advanced Driver-Assistance Systems
- Video and Image Processing
- Smart wireless switch/router
- Machine/Deep Learning acceleration
Block Diagram
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 RV32IMACFDP instructions |
|
| RISC-V single and double precision floating point instruction | Accelerate the processing of high precision arithmetic |
| 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), User (U) and Supervisor (S) Privilege levels | For Linux and advanced operating systems with protection between kernel and user programs |
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 predication features
|
|
Memory Management Unit
|
|
| 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 |
|
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
|
|
ILM & DLM
|
|
| Soft-error protection: ECC or parity for I-Cache and D-Cache, ILM and DLM with SRAM interface | Code and data integrity protection |
| Bus master port: AHB or AXI with 64-bit data, 32 to 64-bit address, AXI with I/D separate or joint bus | User-selectable bus interface for optimal efficiency |
| Bus save port: AHB with 64-bit data, for ILM/DLM accesses | Efficient data transfer between CPU and SoC masters |
| 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
|
|
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 | A25 (w/o DSP, FPU), 28HPC+ | A25 (with DSP, FPU), 28HPC+ |
|---|---|---|
| Frequency (MHz) | 1000 | 1000 |
| Dynamic power (uW/MHz) | 17 | 20 |
| Area (mm2) | 0.084 | 0.165 |
* Configured with cache and MMU. SVT 9-track library, SS corner, 0.81V, -40°C, and with I/O constraint. Power consumption at TT corner, 0.9V, 25°C
