Development of 51 MCU (STC89C52) under Ubuntu-EEWORLD

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Introduction

They are all 8-bit MCUs derived from 8051. STC MCUs have several major series: 89/90/10/11/12/15. The characteristics of each series are as follows

The 89 series is a traditional 8051 microcontroller. The burning method is different, but the function is compatible with the AT89 series. It belongs to the 12T microcontroller.

The 90 series is an improved version of the 89 series, 12T single chip microcomputer

The 10 and 11 series are 1T MCUs with PWM, 4-state IO interface, EEPROM and other functions, but they do not have ADC

The 12 series is a 1T MCU with enhanced functions. The model with the suffix AD has ADC, and the model with the suffix S2 has ADC and dual serial ports.

The 15 series is the latest product, with a high-precision R/C clock integrated inside, and no external crystal oscillator is required.

STC89C52 Parameters

The difference between STC89C52 and STC89C51 is the Flash size, C51 is 4K and C52 is 8K. Both have multiple packages, the most common one is the larger DIP40 wide body dual inline

Flash: 8K bytes

RAM: 512 bytes

Built-in 4KB EEPROM

32-bit I/O

Watchdog timer, MAX810 reset circuit

Three 16-bit timers

4 external interrupts, a 7-vector 4-level interrupt structure and full-duplex serial port

Maximum operating frequency 35MHz, 6T/12T optional

VCC is 5V, do not exceed this voltage.

If you need ADC, you can choose STC12C5A60S2 series. The instruction clock speed of 1T type is faster than that of ordinary STC89 series (12T). Please pay attention to it when doing timing.

Hardware Preparation

Use the common C51 minimum development board

A USB2TTL adapter card

LED + 1K current limiting resistor for viewing output

Development under Ubuntu 20.04

Software

Compilation tool SDCC http://sdcc.sourceforge.net/

Burning tool stcgal https://github.com/grigorig/stcgal

(Optional) Package library HML_FwLib_STC89 https://github.com/MCU-ZHISHAN-IoT/HML_FwLib_STC89

Install sdcc

The sdcc version that comes with Ubuntu 20.04 is 3.8.0, so I plan to compile and install it myself. First read the installation instructions of sdcc at http://sdcc.sourceforge.net/doc/sdccman.pdf

Go to https://sourceforge.net/projects/sdcc/files/sdcc/4.1.0/ to download the latest 4.1.0 source code.

Unzip tar -xvjf sdcc-src-4.1.0.tar.bz2

During the configuration ./configure, it prompted that gputils needed to be installed. I installed it through apt install gputils. There was no error in the ./configure again, but it prompted that this gputils was relatively old and not supported by some devices. Ignore it for now

Compile make, and it prompts that texinfo is missing. Install it through apt install texinfo, and then make again. It should be said that the compilation time is very long. If you only need to compile C51, you can disable some other unnecessary chips during configuration.

Installsudo make install

Check and test the installed sdcc

Run sdcc --version to see if the output is correct, and run sdcc --print-search-dirs to see the location of the library file. The default location of the 8051 library file is /usr/local/share/sdcc/include/mcs51/

Write a piece of code test001.c,

char test;

void main(void) {

test = 0;

}

Compile with sdcc. If the generated result file is normal and there is no error, it means that the installation is fine.

# This step will generate test001.asm and other files

sdcc -c test001.c

# This step will generate test001.ihx and other files

sdcc test001.c

Install stcgal

According to the instructions on the project homepage on Github, install it directly using pip3 install stcgal, and then execute stcgal -h to view the output

Write code and compile with sdcc

Write a test002.c, and control the duty cycle to make the LED on P0.7 produce a breathing light effect.

8052.h is the generic C52 header file that comes with sdcc, not the custom header file for STC89Cxx

Need STC header file, corresponding to STC89C52, you can use stc89.h; corresponding to STC12C5A60S2, you can use stc12.h

#include <8052.h>

#define Led10 P0_7

typedef unsigned int u16;

int atime = 64;

void delay(u16 pms) {

u16 x, y;

for (x=pms; x>0; x--) {

for (y=11; y>0; y--);

}

void ledfade(u16 i) {

Led10 = 0;

delay(i);

Led10 = 1;

delay(atime-i);

}

int main(void) {

u16 a, b;

while(1) {

for (a=0; a for (b=0; b < (atime - a)/4; b++) {

ledfade(a);

}

for (a=atime; a>0; a--) {

for (b=0; b < (atime - a)/4; b++) {

ledfade(a);

}

There are two ways to compile

Add -m parameter, corresponding to 89C52/12C5A60S2, use -mmcs51, if it is Makefile, add it to CCFLAG

Without parameters, specify the path in the header file, for example #include

This is how you use the parameters

sdcc -mmcs51 test002.c

Burn

Burn using stcgal, this page has detailed instructions

For STC89C52 use -P stc89, for STC12C5A60S2 series use -P stc12

stcgal -P stc89 test002.ihx

Waiting for MCU, please cycle power: done # Here you need to turn off and then on the power

Target model:

Name: STC89C52RC/LE52R

Magic: F002

Code flash: 8.0 KB

EEPROM flash: 6.0 KB

Target frequency: 11.010 MHz

Target BSL version: 3.2C

Target options:

cpu_6t_enabled=False

bsl_pindetect_enabled=False

eeprom_erase_enabled=False

clock_gain=high

ale_enabled=True

xram_enabled=True

watchdog_por_enabled=False

Loading flash: 243 bytes (Intel HEX)

Switching to 19200 baud: checking setting testing done

Erasing 2 blocks: done

Writing flash: 640 Bytes [00:00, 1844.10 Bytes/s]

Setting options: done

Disconnected!

It will automatically run after burning. The default baud rate is 19200, which is slow to write. For STC89C52RC, you can directly use the baud rate of 115200, specify it with the -b parameter

stcgal -P stc89 -b 115200 test002.ihx

If there are multiple com ports at the same time, use -p to specify the port

stcgal -P stc89 -b 115200 dist/89/89.hex -p /dev/ttyUSB1

Use the -D parameter to display the interactive information of the serial port.

stcgal -D -P stc89 -b 115200 test002.ihx

Waiting for MCU, please cycle power: <- Packet data: 46 B9 68 00 1C 00 0A 76 0A 72 0A 76 0A 72 0A 76 0A 72 0A 76 0A 72 32 43 FD F0 02 82 5A 16

done