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The hardware and software composition of an ARM architecture chip

An ARM architecture chip hardware and software are two interdependent parts of a chip system.

1. Hardware

Master CPU:

The core of computing and control. The basic architecture of the baseband chip adopts the structure of microprocessor + digital signal processor (DSP). The microprocessor is the control center of the whole chip and will run a real-time embedded operating system (such as Nucleus PLUS). The DSP subsystem is responsible for baseband processing.

Application processors may include multiple microprocessors, as well as GPU.

Microprocessors are different families of ARM products (or x86 architectures), which can be 64-bit or 32-bit. All the units of the CPU are connected by an "internal bus" inside the processor, and its bit width can be 8-64 bits.

Bus:

According to the function, the computer bus can be divided into data bus, address bus and control bus, which are used to transmit data, data address and control signals respectively.

The internal components of CPU are interconnected by the internal bus, while the external bus is the common channel for CPU, memory, input and output devices to transmit information, and each part of the host computer is connected by the bus.

The external device is connected with the external bus through the corresponding interface circuit, thus forming the hardware system. The external bus is connected with the CPU through the bus interface unit BLU.

On-chip bus standard Advanced Microcontroller bus structure AMBA defines the communication standard of high-performance embedded microcontroller.

Three groups of buses are defined: AHB (AMBA high performance bus), ASB (AMBA system bus), and APB (AMBA peripheral bus).

AHB bus is used for high performance, high clock frequency module. AHB provides interfaces for high-performance processors, on-chip memory and off-chip memory, while bridging slow peripherals. DMA, DSP, main memory and so on are connected to the AHB.

ASB bus is mainly used for high performance system modules. ASB is an optional system bus for chip design with high performance characteristics that AHB does not need.

APB bus is used to provide bus technical support for slow peripherals.

APB is an optimized, low-power, compact interface bus that can support a variety of slow peripherals. Because APB is the first bus interface proposed by ARM, APB can bridge every kind of system bus under ARM system.

Peripheral I Pot O port and extended bus:

GPIO universal port, UART serial port, I2C, SPI, SDIO, USB, etc., CPU and extended chips, devices, and the interface for communication between two CPU, such as baseband processor and application processor.

Generally speaking, the chip will support a variety of interfaces, and design a general software driver platform driver.

Storage parts and storage management devices:

Rom, Ram, Flash and controller. Processor systems may contain many types of memory components, such as Flash, SRAM, SDRAM, ROM and Cache, which are used to improve system performance. Different chips will use different memory control combinations.

Peripherals:

Power and power management, reset circuit and watchdog timing reset circuit (the former is the system power-on operation, the latter is Reset or timeout error operation), clock and counter, interrupt controller, DMA, input / output (such as keyboard, monitor, etc.), camera, etc.

two。 The software on the software chip mainly includes Boot code, operating system, application program and firmware of hardware.

The Boot program guides the startup of the device, which is a section of Mini Program that runs before the operating system kernel runs after the device is powered on.

Through this Mini Program, we can initialize the hardware devices and establish a memory space mapping, so as to bring the software and hardware environment of the system to an appropriate state, so as to prepare the correct environment for the final call of the operating system kernel.

Operating system is a computer program that manages and controls computer hardware and software resources. Its five major management functions are:

1 processor management, including process control, synchronization, communication and scheduling.

(2) memory management, including memory allocation, protection and expansion, address mapping.

(3) equipment management, including equipment distribution, processing and so on.

File management, mainly including file storage space management, directory management, file reading and writing and protection.

(5) Job management, including task, interface management, human-computer interaction, voice control and virtual reality.

The operating systems on the application processor include Android, IOS, etc., needless to say; on the baseband processor, a RTOS (such as Nucleus PLUS) runs to manage the communication between tasks and components on the entire baseband system.

An application is a program that is developed to run on the operating system in order to accomplish one or more specific tasks.

On the application processor, combined with the operating system API and library functions, users can develop a variety of applications; on the baseband processor, there is generally only a small amount of necessary software support.

Hardware firmware simplifies the interaction between software and hardware, making the hardware easier to manipulate.

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