89c51 pin diagram pin diagram pin function description

89c51 pin diagram pin diagram

Pin function description

89C51 external pin diagram: (can be copied directly into the ASM program file and used for comments, very convenient)

; ┏━┓┏━┓
; P1.0 ┫1 ┗┛40┣ Vcc
; P1.1 ┫2 39┣ P0 .0    
; P1.2 ┫3 38┣ P0.1    
; P1.3 ┫4 37┣ P0.2    
; P1.4 ┫5 36┣ P0.3    
; P1.5 ┫6 35┣ P0.4    
; ┫7 34┣ P0.5    
; P1.7 ┫8 33┣ P0.6    
; RST/Vpd ┫9 32┣ P0.7    
; RXD P3.0 ┫10 31┣ -EA/Vpp (internal 1/external 0 program address selection)
; TXD P3.1 ┫11 30┣ ALE/-P (address latch output)
; -INT0 P3.2 ┫12 29┣ -PSEN (external program read strobe output)
; -INT1 P3.3 ┫13 28 ┣     P2.7    
;    ​     ​┣               P2.3 ; X2     ┫18             23┣ P2.2     ; ): Typical value +5V.           Vss (pin 20): connected to low level.         ②The external crystal oscillators           X1 and X2 are connected to both ends of the crystal respectively. When using an external clock signal, X2 is connected to the oscillation signal and X1 is connected to ground .         ③Input and output port pins:           Port P0: I/O bidirectional port. When used as an input port, the software should first set "1".           P1 port: I/O bidirectional port. When used as an input port, the software should first set "1".           P2 port: I/O bidirectional port. When used as an input port, the software should first set "1".           P3 port: I/O bidirectional port. When used as an input port, the software should first set "1".         ④Control pins:           RST/Vpd, ALE/-PROG, -PSEN, -EA/Vpp form the control bus of MSC-51.           RST/Vpd (pin 9): reset signal input terminal (active high level).           Second function: Add +5V backup power supply to protect RAM information from loss during power outage.           ALE/-PROG (pin 30): address latch signal output.           Second function: programming pulse input.           -PSEN (pin 29): external program memory read strobe signal.           -EA/Vpp (31 pin): external program memory enable terminal.           Second function: programming voltage input terminal (+21V).