CN206849475U

CN206849475U - A kind of LCD1602 liquid crystal displays parallel-expansion circuit

Info

Publication number: CN206849475U
Application number: CN201720336154.7U
Authority: CN
Inventors: 刘志壮; 黄堂森
Original assignee: Hunan University of Science and Engineering
Current assignee: Hunan University of Science and Engineering
Priority date: 2017-04-01
Filing date: 2017-04-01
Publication date: 2018-01-05
Anticipated expiration: 2027-04-01

Abstract

The utility model is related to a kind of LCD1602 liquid crystal displays parallel-expansion circuit, including single-chip microcomputer, LCD1602 liquid crystal displays, logic gates, LCD1602 8 data ports connect the P0 mouths of single-chip microcomputer, Read-write Catrol RW, order RS control lines connect the P2 mouths of single-chip microcomputer, LCD1602 enabled control line connects the output end of logic NAND gate circuit, the input of logic NAND gate circuit meets the access hole P3.7 of single-chip microcomputer, P3.6, form the outer reading and writing data parallel-expansion circuit of piece, display output and read data operation to LCD1602 are completed using data read-write operation outside piece.

Description

A kind of LCD1602 liquid crystal displays parallel-expansion circuit

Technical field

The utility model is related to electronic technology, singlechip technology and lcd technology, especially controls liquid with single-chip microcomputer The technology of crystal display.

Background technology

For liquid crystal display using more and more common, the position datawire of liquid crystal display generally use 8 transmits data, passes through journey Sequence completes to write data time sequence, and the program generally comprises write order and writes two functions of data.Such way adds journey Sequence complexity, the utility model increase a NAND gate circuit on hardware, write order and to write data be all that an instruction is completed, Simplify program.

The content of the invention

The utility model is in order to simplify the display program of LCD1602 liquid crystal displays, using parallel-expansion technology.The practicality It is new including single-chip microcomputer（1）, LCD1602 liquid crystal displays（2）, logic NAND gate circuit（3）；LCD1602 liquid crystal displays（2） Eight bit data mouth connect single-chip microcomputer（1）P0 mouths, LCD1602 liquid crystal displays（2）Read-write Catrol RW, order RS mouth order pieces The P2 mouths of machine, LCD1602 liquid crystal displays（2）Enabled control line connect logic NAND gate circuit（3）Output end, single-chip microcomputer （1）Read-write Catrol bus connection logic NAND gate circuit（3）Two inputs.Single-chip microcomputer（1）Using AT89C52, its P0 Eight pins 39,38,37,36,35,34,33,32 of mouth connect LCD1602 liquid crystal displays respectively（2）Eight pins of data port 7、8、9、10、11、12、13、14；The P2.7 and P2.6 of AT89C52 P2 mouths, i.e. pin 28,27 connect LCD1602 liquid crystal respectively Display（2）RS, RW be pin 4,5；Logic NAND gate circuit（3）Using digit chip 74LS00, AT89C52 read-write control Line P3.7, P3.6 processed are the pin 1,2 that pin 17,16 is connected respectively to digit chip 74LS00, and digit chip 74LS00's draws Pin 3 is connected to LCD1602 liquid crystal displays（2）Enable Pin EN be its pin 6.

The beneficial effect of the utility model is to be operated by hardware time order instead of software timing, simplifies program code, optimization Program.

Brief description of the drawings

Fig. 1 is schematic diagram, and Fig. 2 is LCD1602 timing diagrams, and Fig. 3 is the outer data read-write operation sequential of AT89C52 single chip microcomputers Figure；

In Fig. 1,1 it is single-chip microcomputer, 2 is LCD1602 liquid crystal displays, 3 is logic gates, 4 is adjustable resistance.

Embodiment

The utility model includes single-chip microcomputer（1）, LCD1602 liquid crystal displays（2）, logic NAND gate circuit（3）； LCD1602 liquid crystal displays（2）Eight bit data mouth connect single-chip microcomputer（1）P0 mouths, LCD1602 liquid crystal displays（2）Read-write Control RW, order RS mouths connect the P2 mouths of single-chip microcomputer, LCD1602 liquid crystal displays（2）Enabled control line connect logic NAND gate electricity Road（3）Output end, single-chip microcomputer（1）Access hole connection logic NAND gate circuit（3）Two inputs.Single-chip microcomputer（1）Adopt With AT89C52, eight pins of its P0 mouth 39,38,37,36,35,34,33,32 connect LCD1602 liquid crystal displays respectively（2）'s Eight pins of data port 7,8,9,10,11,12,13,14；The P2.7 and P2.6 of AT89C52 P2 mouths, i.e. pin 28,27 distinguish Connect LCD1602 liquid crystal displays（2）Pin 4,5；Logic NAND gate circuit（3）Using digit chip 74LS00, AT89C52 Read-write control line P3.7, P3.6 be pin 1,2 that its pin 17,16 is connected respectively to digit chip 74LS00, digit chip 74LS00 pin 3 is connected to LCD1602 liquid crystal displays（2）Enable Pin EN be its pin 6.Single-chip microcomputer（1）Transmit data To LCD1602 liquid crystal displays（2）By data write operation outside piece, transmission command address is 0x3F00, and Q address is 0xBF00, i.e., it is write order to write data into address 0x3F00 by data write operation outside piece, writes data into address 0xBF00 To write data.

In the present embodiment, the P2.7 and P2.6 of AT89C52 P2 mouths connect LCD1602 liquid crystal displays respectively（2）RS, It is write order when R/W, P2.7P2.6 are 00, to write data when P2.7P2.6 is 10, other six of P2 mouths are set to high level, P0 Mouth is unused for low order address.So the outer address of write order piece is 0x3F00, it is 0xBF00 to write the outer address of data slice.LCD1602 liquid Crystal display（2）The Enable Pin of pin 6, be automatically performed sequential operation by data write operation outside single chip microcomputer.

In the present embodiment, the resistance of adjustable resistance (4) is 2.2k, and LCD1602 pin 3 connects adjustable resistance (4), regulation Adjustable resistance（4）To change LCD1602 contrast.

In the present embodiment, portion of program code is as follows：

/ * liquid crystal displays write order and write FPDP address predefine */

#define LCD1602_COM XBYTE [0x3F00]

#define LCD1602_DATA XBYTE [0xBF00]

/ * write orders and write data program operation */

LCD1602_COM=0x80;// send display address

LCD1602_DATA’0’;// write-in display data

Pass through single-chip microcomputer（1）The outer data read-write operation of piece, software timing completion pair is replaced by single-chip microcomputer hardware time order LCD1602 liquid crystal displays（2）Read-write Catrol, simplify program.

Claims

1. a kind of LCD1602 liquid crystal displays parallel-expansion circuit, its feature include single-chip microcomputer（1）, LCD1602 liquid crystal displays （2）, logic NAND gate circuit（3）；LCD1602 liquid crystal displays（2）Eight bit data mouth connect single-chip microcomputer（1）P0 mouths, LCD1602 liquid crystal displays（2）Read-write Catrol RW, order RS mouths connect the P2 mouths of single-chip microcomputer, LCD1602 liquid crystal displays（2） Enabled control line connect logic NAND gate circuit（3）Output end, single-chip microcomputer（1）Read-write Catrol bus connection logic NAND gate Circuit（3）Two inputs.

A kind of 2. LCD1602 liquid crystal displays parallel-expansion circuit according to claim 1, it is characterized in that single-chip microcomputer（1） Using AT89C52, eight pins of its P0 mouth 39,38,37,36,35,34,33,32 connect LCD1602 liquid crystal displays respectively（2） Eight pins 7,8,9,10,11,12,13,14 of data port；The P2.7 and P2.6 of AT89C52 P2 mouths, i.e. 28,27 points of pin Lian Jie not LCD1602 liquid crystal displays（2）RS, RW be pin 4,5；Logic NAND gate circuit（3）Using digit chip 74LS00, AT89C52 read-write control line P3.7, P3.6 are the pin that pin 17,16 is connected respectively to digit chip 74LS00 1st, 2, digit chip 74LS00 pin 3 are connected to LCD1602 liquid crystal displays（2）Enable Pin EN be its pin 6.