51 Microcontroller Naming Rules
A simple example
89C51:
8 represents an 8-bit microcontroller;
9 represents flash memory, where 0 indicates no ROM, 7 indicates EEPROM memory, and C indicates CMOS technology, while S indicates ISP programming method;
1 represents the internal program memory capacity, with the size corresponding to this digit * 4KB. 89C52: 8KB capacity;
Naming Rules
This article introduces the naming rules of the two most common microcontroller manufacturers: AT89S51 & STC89C51:
First, let’s discuss the AT series microcontrollers from ATMEL. The model coding of the 89 series microcontrollers consists of three parts: prefix, model, and suffix. The format is as follows: AT89C XXXXXXXX, where AT is the prefix, 89CXXXX is the model, and XXXX is the suffix. Below, each of these three parts will be explained, along with the representation and significance of related parameters.
(1) The prefix consists of the letters “AT”, indicating that this device is a product of ATMEL.
(2) The model is represented by 89CXXXX or 89LVXXXX or 89SXXXX, etc.
In “89CXXXX”, 9 indicates that it contains internal Flash memory, and C indicates it is a CMOS product.
In “89LVXXXX”, LV indicates a low-voltage product.
In “89SXXXX”, S indicates it contains a serial download Flash memory.
In this part, “XXXX” indicates the device model number, such as 51, 1051, 8252, etc.
(3) The suffix consists of four parameters, each with different representations and meanings. There is a “1” number separating the model and suffix parts. The first parameter X in the suffix indicates speed, with the following meanings:
X=12, indicates a speed of 12MHz;
X=20, indicates a speed of 20MHz;
X=16, indicates a speed of 16MHz;
X=24, indicates a speed of 24MHz;
The second parameter X in the suffix indicates packaging, with the following meanings:
X=D, indicates ceramic package.
X=Q, indicates PQFP package.
X=J, indicates PLCC package.
X=A, indicates TQFP package.
X=P, indicates plastic dual in-line DIP package.
X=w, indicates bare chip.
X=S, indicates SOIC package.
The third parameter X in the suffix indicates temperature range, with the following meanings:
X=C, indicates commercial product, temperature range of 0~70°C.
X=I, indicates industrial product, temperature range of -40~85°C.
X=A, indicates automotive product, temperature range of -40~125°C.
X=M, indicates military product, temperature range of -55~150°C.
The fourth parameter X in the suffix indicates the processing condition of the product, with the following meanings: X is empty, indicating standard processing technology.
X=/883, indicates processing technology follows MIL-STD-883 standards.
For example: a microcontroller model named “AT89C51-12PI” indicates that this microcontroller is an ATMEL Flash microcontroller, with an internal CMOS structure, speed of 12 MHz, packaged in plastic DIP, and is an industrial product manufactured under standard processing technology.
Typeset by: Ma Yongqi
Reviewed by: Song Zize
