Stc89c52 MCU is 51 & 52 series MCU, it is similar to AT89C52, there is no big difference, it can be directly replaced, but there is an internal EEPROM space, the serial port can download the program, the instruction execution speed is doubled.
The STC89C52 is a low-voltage, high-performance COMOS8 microprocessor with 8K bytes of Programmable Readable Memory (FPEROM-Flash Programable and Erasable Read Only Memory). The device is fabricated using ATMEL's dense-non-volatile memory manufacturing technology and is compatible with the industry-standard MCS-51 instruction set and output pins.
The following is a matrix keyboard program under the stc89c52 microcontroller, P0 port keyboard, displayed in the P2 port.
#include
#define uchar unsigned char
#define uint unsigned int
Sbit key1=P3^2;
Sbit key2=P3^3;
Uchar code tab[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71,0x00}; //Define the work of eight lights status.
Uchar code wep[]={0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07};
Void yanshi(uint t)
{
While(--t);
}
Void main()
{
Uchar han,lei,key;
While(1)
{
P0 = 0xf0; / / Initialize to the switch state. 11110000
Han=P0; //The han variable reads the value of the P0 port. Scan the keyboard for the first time.
Han=han&0xf0; //The han variable is associated with 0xf0.
// If the result is equal to the initial value of the P0 port (0xf0), no key is pressed.
// If the result is not equal to the initial value of P0 (0xf0), it means there is a key press.
If(han!=0xf0)
Yanshi (125 * 5); / / delay debounce.
If(han!=0xf0) //The statement is executed here to indicate that there is a key press.
{ // For example, press the S1 button. Then P0=1110 0000
Lei=P0&0xf0; //lei reads the value of port P0.
Lei=lei|0x0f; //lei=11101111
P0=lei; //P0=11101111
Han=P0; //han=11101110 scan the keyboard for the second time,
//Because the button S1 is still closed.
Han=han&0x0f; //han=00001110
Lei=lei&0xf0; //lei=11100000
Key=han+lei;
}
Switch(key)
{
Case 0xee: P2=tab[0]; break;
Case 0xde: P2=tab[1]; break;
Case 0xbe: P2=tab[2]; break;
Case 0x7e: P2=tab[3]; break;
Case 0xed: P2=tab[4]; break;
Case 0xdd: P2=tab[5]; break;
Case 0xbd: P2=tab[6]; break;
Case 0x7d: P2=tab[7]; break;
Case 0xeb: P2=tab[8]; break;
Case 0xdb: P2=tab[9]; break;
Case 0xbb: P2=tab[10]; break;
Case 0x7b: P2=tab[11]; break;
Case 0xe7: P2=tab[12]; break;
Case 0xd7: P2=tab[13]; break;
Case 0xb7: P2=tab[14]; break;
Case 0x77: P2=tab[15]; break;
}
}
}
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