Follow+Star Public Account Number, don’t miss exciting content

Author | strongerHuang

WeChat Official Account | Embedded Column

The naming rules for ARM are a bit complex, with some changes between the early and current naming conventions. For the average person, just understanding a few major naming rules is enough.

ARM naming is divided into Instruction Set Architecture, Processor Architecture, Processor Model three categories of naming rules:

1. Instruction Set Architecture

Instruction set architecture naming format:

Armv + [n] + [variants] + [x(variants)]

Armv：Fixed character, i.e., ARM Version

n：Instruction set version number, to date, 9 series of ARM architecture versions have been released, so n=[1~9]

variants：Variants

x(variants)：Indicates that the specified variant after x is not supported

ARM + [x][y][z] + [variants]

x：Processor series, there are multiple series such as 6, 7, 9, 11

y：Memory Management/Protection Unit

z：Cache

Variants have the following letters available:

T：Supports Thumb instruction set

D：Supports on-chip debugging

M：Supports fast multipliers

I：Supports Embedded ICE, supports embedded trace debugging

E：Supports enhanced DSP instructions

J：Supports Jazelle

(F)：Equipped with vector floating-point unit VFP

-S：Synthesizable version

• Cortex-M0, Cortex-M3, Cortex-M4

• Cortex-R4, Cortex-R5

• Cortex-A55, Cortex-A73

After understanding the ARM processor naming rules, let’s look at the differences between ARM7, ARM9, s3c2410, STM32, and Cortex-M3.

1. ARM7

ARM7 is a processor series (major version, or ARM7 family), which contains many types of processors.

Most adopt the ARMv4T core architecture, but some processors take ARMv3 or ARMv5TEJ core. This series adopts the von Neumann architecture.

The ARM7 series was launched in 1993, classic ARM7 processors include ARM7TDMI, ARM7EJ-S, etc. (Early STM32 products like STM7 also use the ARM7TDMI 32-bit RISC core).

2. ARM9 and s3c2410

After ARM7 comes ARM9, there is actually a transitional product ARM8 (just like Win7 jumped directly to Win10).

ARM9 was still quite popular during my school days, and there are still many learning materials about ARM9.

The classic s3c2410 is actually a processor based on the ARM920T core, and after S3C2410, S3C2416, S3C2440, etc. can be said that students learning embedded Linux all know of their existence, and many Linux development boards and materials on the market are designed based on these processors.

Currently, many embedded Linux development boards are based on NXP’s iMX.6 processor (Cortex-A9).

3. STM32 and Cortex-M3

STM32 is familiar to those learning microcontrollers and embedded development; it is a processor based on the Cortex-M core from ST (STMicroelectronics), which includes multiple series (STM32F0, F1, F4, L0, L1, G0, G4, etc.).

Cortex-M3 is just a core of an ARM processor, and many semiconductor companies develop their products based on the Cortex-M3 core.

Finally, for beginners, there is no need to get too caught up in the relationships and differences between these processors.

In the case of uncertainty, just choose a currently popular processor to learn from, buy a development board to start learning, and code and think more.

Reply in the background with ‘Science Popularization Knowledge’ or ‘Embedded Software and Hardware Knowledge’ to read more related articles.

Click “Read Original” to see more shares, and feel free to share, bookmark, like, and view.