Design of AT89S8252 microcontroller to realize contact IC card reading and writing control

Since I was in high school, the meal cards used in our school have been contact-type IC cards. There are also many IC card phones distributed on campus. After going to college, the campus cards used by the school are non-contact and radio frequency IC cards. Therefore, I became interested in IC cards. In the process of learning microcontrollers, I learned that microcontrollers can realize reading and writing control of IC cards. Based on referring to relevant materials, I learned to use microcontrollers to realize contact IC card reading and writing control.

Main components:

1. AT89S8252 microcontroller chip. This chip has an SPI interface and can be used to read and write IC card chips.

2. The IC card chip AT45D041A, which uses a serial data interface compatible with the SPI interface, supports in-system reprogramming and can be used for the storage of digital voice, images and data.

Test flow chart:

Test circuit diagram:

Test program code:

//ICRdWr.h program

#ifndef _ICRDWR_H // Prevent ICRdWr.h from being referenced repeatedly

#define _ICRDWR_H

#include //Important header file references

#define uchar unsigned char

#define uint unsigned int

/* Instruction macro definition*/

#define BUFFER_1_WRITE 0x84 // buffer1 write instruction code

#define B1_TO_MM_PAGE_NO_ERA 0x88 // Buffer1 write main memory page instruction code without online erasure

#define MM_PAGE_READ 0xD2 // Main memory page read instruction code

#define STAT_REG_READ 0xD7 // Status register read instruction code

#define DATA_IN_MAX_LEN 8

#define DATA_OUT_MAX_LEN 8

uint page_start_addr; // Starting byte address in the page

uint page_addr; // Page address, the lower 9 bits of the 16 bits are valid bits

uint buf_start_addr; //The starting byte address in the buffer, the lower 11 bits of the 16 bits are valid bits

uchar data_in［DATA_IN_MAX_LEN］; //Data to be written to the IC card

uchar data_out［DATA_OUT_MAX_LEN］; //The data to be read from the IC card

#endif

//ICRdWr.c program

#include “ICRdWr.h”

/* Delay t milliseconds*/

void delay(uint t)

{

uint i;

while(t--)

{

/* For 11.0592M clock, the delay is about 1ms */

for (i=0;i<125;i++)

{}

}

}

/* Get the function that needs to be stored in the IC card data */

void getdata()

{

// This function is simplified as follows:

uchar i;

for (i=0;i«8;i++)

data_in［i］=i+1;

}

/* Write the SPDR register of the microcontroller AT89S8252, and the data is serially output to the IC card chip through the SPI port */

void write_spi(uchar dat)

{

SPDR = dat;

while (!(SPSR & 0x80)); // Wait for a transfer to complete

}

/* Get IC card chip status function */

uchar IC_stat(void)

{

P1_1 = 0; // Enable IC card chip;/cs=0

write_spi(STAT_REG_READ); // Write read IC card chip status command

write_spi(0x00); // Write don't care bits

P1_1 = 1; //Disable IC card chip;/cs=1

return SPDR; // Return IC card chip status byte

}

/* Write IC card chip function: write data into the buffer, if the buffer is full,

Then write the data in the buffer to the main memory page*/

void write_to_IC(uchar dat)

{

uchar stat;

/* Check whether the IC card chip is busy*/

stat = IC_stat();

while ((stat&0x80)==0x00);

/* Write data to buffer */

P1_1 = 0; // Enable IC card chip;/cs=0

write_spi(BUFFER_1_WRITE); // buffer1 write instruction code

write_spi(0x00); //Write 8 don't care bits

write_spi((uchar)(buf_start_addr》》8)); //Write 7-bit irrelevant bits plus the 1st bit of the 9-bit buffer start byte address

write_spi((uchar)buf_start_addr); //Write the last 8 bits of the 9-bit buffer start byte address

write_spi(dat); //Write data

P1_1 = 1; // Disable IC card chip; end buffer write command

buf_start_addr++; // Next buffer starting byte address

/* If the buffer is full, write the data in the buffer to the main memory page */

if (buf_start_addr》263)

{

buf_start_addr = 0; //buffer start byte address reset to 0

if (page_addr "2047") // If the main memory page is not full

{

/* Write buffer data to main memory page*/

P1_1 = 0; // Enable IC card chip;/cs=0

write_spi(B1_TO_MM_PAGE_NO_ERA); // Write buffer1 write main memory page instruction code without online erasure

write_spi((uchar)(page_addr》》7)); // Write 4 reserved bits plus the high 4 bits of the 11-bit page address

write_spi((uchar)(page_addr《》1)); //Write the lower 7 bits and 1 don't care bit of the 11-bit page address

write_spi(0x00); //Write 8 more irrelevant bits

P1_1 = 1; // Disable the IC card chip; end the buffer write main memory page instruction without online erasure

page_addr++; // Next page address

}

}

}

/* Read IC card chip function, if one page is read, read the next page */

uchar read_from_IC()

{

uchar stat;

uchar tmp;

/* Check whether the IC card chip is busy*/

stat = IC_stat();

while ((stat&0x80)==0x00);

/* Read data from the main memory page */

P1_1 = 0; // Enable IC card chip;/cs=0

write_spi(MM_PAGE_READ); //Write the main memory page read instruction code

tmp = (uchar)(page_addr》》7);

write_spi(tmp); // Write 4 reserved bits plus the high 4 bits of the 11-bit page address

tmp = (uchar)(page_addr《》1)|((uchar)(page_start_addr》》8)&0x01);

write_spi(tmp); //Write the lower 7 bits of the 11-bit page address and the highest bit of the 9-bit page starting byte address

tmp = (uchar)(page_start_addr);

write_spi(tmp); //Write the lower 8 bits of the 9-bit page starting byte address

write_spi(0x00); //Write 8 don't care bits

write_spi(0x00); //Write 8 don't care bits

write_spi(0x00); //Write 8 don't care bits

write_spi(0x00); //Write another 8 bits of don't care bits, totaling 32 bits of don't care bits.

write_spi(0xff); //Write 8-bit meaningless value to ensure completion of reading out one byte of data

P1_1 = 1; // Disable IC card chip; end main memory page read command

page_start_addr++; // Starting byte address in the next page

/* If one page is read, read the next page*/

if (page_start_addr》263)

{

page_start_addr = 0; //Reset the page start byte address to 0

if (page_addr "2047") // If the main memory page has not been read

page_addr++; // Next page address

}

return SPDR; // Return the read data

}

Continuing from the previous program:

/* Main function */

void main()

{

uchar i;

P1_0 = 1; // /RST pin is set high

/* SPIE=0, SPE=1, DORD=0, MSTR=1, CPOL=CPHA=1, SPR1=0, SPR0=1*/

SPCR=0x5d;

buf_start_addr = 0;

page_start_addr = 0;

page_addr = 0;

/* Get the data that needs to be written to the IC card and store it in data_in[]*/

getdata();

/* Write the data stored in data_in[] to the IC card*/

for (i=0;i

{

write_to_IC(data_in[i]);

delay(2); //delay 2ms

}

delay(10); // Delay 10ms

buf_start_addr = 0;

page_start_addr = 0;

page_addr = 0;

/* Read the data from the IC card and store it in data_out[]*/

for (i=0;i

{

data_out［i］ = read_from_IC();

delay(2); //delay 2ms

}

while(1);

}