CN101344767A - Non-encoded keyboard and display interface of watercraft embedded micro-controller - Google Patents

Abstract

The invention provides an interface of a non-coding keyboard and a monitor of an embedded ship microcontroller, in particular relates to an interface of a small keyboard and an LCD/LED monitor applied to intelligent instruments to overcome the defect that the existing microcontroller keyboard needs multiple varieties and large quantities of chips, which take a large area of the printed circuit board and therefore reduce the design flexibility. The interface comprises a logic circuit which is composed of programmable logic components. The input and the output ends of the logic circuit are respectively connected with a microcontroller and a monitor. The invention provides a new chip-based design method. Complicated programmable logic components are designed into the interface of the non-coding keyboard and the LCD/LED monitor of the embedded microcontroller so that only one chip is used for providing a keyboard-LCD/LED monitor interface based on a single chip computer system bus, and the interface not only does not occupy the single chip computer system resource, but also expands the external capacity of the system.

Description

The nonencoded keyboard of watercraft embedded micro-controller and display interface device

Technical field

The present invention relates to microcontroller and keyboard, display interface device technical field, specifically, relate to the nonencoded keyboard and the display interface device of watercraft embedded micro-controller, be specially adapted to the keypad and the LCD/LED display interface device of boats and ships smart instrumentation.

Background technology

Keyboard and LCD/LED display are one chip microcomputer control system man-machine interfaces commonly used, control and Displaying Meter as some teaching and research equipment and marine system, the user is by keyboard on the panel and display screen, and the available conversations mode is selected measurement function, and parameter is set.The intelligent instrumentation core is a single-chip microcomputer, because single-chip microcomputer is mainly used in the control field, custom calls microcontroller MCU (MicrControler Unit) to single-chip microcomputer, microcontroller is in order to realize various measurements and control function, the single-chip microcomputer function is strong, volume is little, when using, normally be in the core status of control system and incorporate wherein, so claim embedded microcontroller again., be integrated on the chip piece the microcomputer critical piece from the structure single-chip microcomputer.Microcomputer is measured and control system also must comprise peripherals and communication facilities but form, as keyboard and display.

These real systems are often wished the compact conformation of device, require to take less MCU I/O mouth resource, require to be connected by an interface for keyboard and light-emitting diode display; Require the connecting line of keypad/display and interface to lack simultaneously; Require interface that good versatility is arranged.Therefore, the high-performance interface of the keyboard of development Single Chip Microcomputer (SCM) system and LCD/LED display has actual application value.

The method that the Single Chip Microcomputer (SCM) system periphery circuit design is general is to expand with general programmable interface (as 8255) and standard integrated chip, connects by printed circuit board (PCB), builds system.This method for designing, required chip kind is many, quantity is big, and it is big to occupy the printed-wiring board (PWB) area, does not almost have dirigibility to say during design, restricts the development of interfacing greatly.

Chinese patent ZL 200520046271.7 provides a kind of keyboard and light-emitting diode display interface module based on essential bus, comprise essential bus, keyboard, display interface device chip 8279, attachment plug, it is characterized in that: the control signal of a. essential bus is connected with the control line mouth of control chip by two-way control line and chip for driving, this two-way control line also with chip for driving, dynamically chip is connected; The data-signal of essential bus is connected with the bidirectional data line mouth of control chip by bidirectional data line and chip for driving; The address signal of essential bus is connected with chip for driving by unidirectional address wire, high position in the address is translated yard chip selectively by sheet and is produced a chip selection signal and be connected with the chip selection signal line of the control line mouth of control chip then, and the low level signal in the address is directly connected to the address wire mouth of control chip; B. the keyboard state end of control chip links to each other with two status key by attachment plug, the scanning delivery outlet of control chip is connected with the keyboard scan coding chip with the reading scan coding chip by the dynamic scan line, keyboard scan coding chip output keyboard scanning signal, output to the keyboard array by attachment plug, the keyboard scan of control chip returns mouth and links to each other with the keyboard array by attachment plug, the display control signal control of the controlled chip of reading scan coding chip, output reading scan signal, this sweep signal is selected the signal chip for driving by the position, the reading scan line selects signal wire to be connected with attachment plug with the position of 16 light-emitting diode displays, the display segments of control chip selects delivery outlet to select the signal chip for driving by the section code selection line section of being connected to, and selects signal wire to be connected by attachment plug with the section of 16 light-emitting diode displays again.Because adopt general-purpose chip and traditional method for designing, required chip kind is many, quantity is big, line is many, it is big to occupy the printed-wiring board (PWB) area, can not apply to the keypad and the LCD/LED display interface device of smart instrumentation.

Summary of the invention

The nonencoded keyboard and the display interface device that the purpose of this invention is to provide a kind of watercraft embedded micro-controller, be specially adapted to the keypad and the LCD/LED display interface device of boats and ships smart instrumentation, the required chip kind of existing microcontroller keyboard interface is many, quantity is big to overcome, it is big to occupy the printed-wiring board (PWB) area, does not almost have the defective of dirigibility during design.

Technical matters solved by the invention can realize by the following technical solutions:

A kind of nonencoded keyboard of watercraft embedded micro-controller and display interface device comprise the logical circuit that programmable logic device (PLD) constitutes, and it is characterized in that: the input end of described logical circuit links to each other with display with microcontroller respectively with output terminal.

Among the present invention, described display comprises LCD display and/or light-emitting diode display, described logical circuit comprises the light-emitting diode display keyboard logic circuit that LCD display logical circuit that keyboard is connected with LCD display and keyboard are connected with light-emitting diode display, and wherein the logical circuit that is connected with LCD display of keyboard adopts unique address mapping logic design.

Described LCD display address mapping logic circuit is made of gate circuit, address latch, address decoder and driving output circuit, and described gate circuit input end connects the read-write pin of microcontroller, and output terminal connects the clock pin of LCD display, realizes the control input; The read-write pin of microcontroller links to each other with the read-write pin of LCD display by address decoder simultaneously, thereby the output port of microcontroller is connected the structure of realizing data bus with the data port of LCD display, and 16 of microcontroller address buss are to realize being connected with LCD display through the address latch in the programmable logic device (PLD), address decoder, driving output.

LCD display address mapping logic circuit can be made of functional block, each functional block by 18 independently macroelement form, each macroelement can be realized the function of a combinational circuit or register.Can bypass (this register is left in the basket) in when design, thus macroelement is only used as combinational logic, the register of macroelement can be configured to d type flip flop or T trigger, and we are configured to d type flip flop as latch, and clock is as the control input.And, in a functional block FB, realize latch like this, the code translator function latch output enable decoding input.

Described light-emitting diode display keyboard logic circuit comprises serial-in parallel-out register and three-state buffer, serial-in parallel-out register is connected with the microcontroller serial line interface, one of two pins is for making the data lead-in wire, another is as clock cable, and the output pin of serial-in parallel-out register connects light-emitting diode display segment encode line; The bit code sweep trace of light-emitting diode display connects the output port of microcontroller by three-state buffer.

The invention provides a kind of based on new based on chip design method, be designed to the nonencoded keyboard and the LCD/LED display interface device of embedded microcontroller with CPLD, this interface is specially adapted to the keypad and the LCD/LED display of smart instrumentation.

Compare with the circuit of general method for designing, only provide a keyboard and a LCD/LED display interface device based on the Single Chip Microcomputer (SCM) system bus with a slice chip, this interface does not only take the Single Chip Microcomputer (SCM) system resource, goes back the external ability of expanding system.Nonencoded keyboard and LCD/LED display interface device are realized by complex programmable logic device (CPLD) XC9572XL programming, have reduced kind, the quantity of chip, have simplified board design again, make the system architecture compactness, and the Performance And Reliability of system improves.Single-chip microcomputer and the extremely strong complementarity of large-scale complex programmable logic device (PLD) are fully used in system design, thus the embedded instrumentation instrument of the high-performance formed of the circuit structure that combines of two class devices and high reliability for the instrument and meter system particularly the marine instrument, system a new approach is provided.

Description of drawings

Fig. 1 is LCD display of the present invention/keyboard interface schematic diagram.

Fig. 2 is LCD display address mapping logic circuit theory diagrams of the present invention.

Fig. 3 writes sequential chart for HD44780 of the present invention.

Fig. 4 reads sequential chart for HD44780 of the present invention.

Fig. 5 is light-emitting diode display of the present invention/keyboard interface schematic diagram.

Fig. 6 is light-emitting diode display keyboard logic circuit theory diagrams of the present invention.

Embodiment

For technological means, creation characteristic that the present invention is realized, reach purpose and effect is easy to understand, below in conjunction with concrete diagram, further set forth the present invention.

Embodiment 1

Programmable logic device (PLD) PLD (Programmable Logic Device) is that the ASIC of new generation (Application Specific Integrated Circuits) that grows up in the later stage eighties 20th century manufactures and designs for the user specially.After the nineties in 20th century, complex programmable logic device (CPLD) (ComplexProgrammable LogicDevice) becomes PLD product main flow, Xilinx XC9500 family device can provide the complete set of solutions from the simplest PAL comprehensive Design to state-of-the-art real-time hardware field upgrade, but it is semi-manufacture, needs the technician to be developed to the product of oneself.Use complex programmable logic device (CPLD), be actually CPLD is designed.

Using the CPLD device first step is selector, the t of XC9572XL device _PDReach 3.5ns, the macroelement number has 72, and system clock can reach 196MHz, and native system adopts 100 TQFP encapsulation XC9572XL to reach designing requirement.It should be noted that: 1) device adopts flash technology (Fast FLASH), is provided at in-system programming, and minimum program/erase number of times reaches 10000 times, with E ²CMOS technology is compared, and power consumption obviously reduces.2) the driving load capacity is strong, and the load current of each input/output end port can reach 24mA, and directly driving LED shows, saves the driving circuit of interface, dwindles the printed-wiring board (PWB) area.

Using CPLD device gordian technique is chip design, traditional design method generally uses the logic algebra abbreviation, less and to reach designing requirement be standard with used door number, and CPLD design is that the unit designs with functional block FB (Function Block), and is minimum and to reach designing requirement be standard with used FB.To rationally use XC9572XL, must be very familiar to XC9572XL CPLD device, grasp its core technology, the present invention promptly adopts this device.

XC9572XL is made up of 4 functional block FB (Function Block) and I/O piece I0B, and the subsystem that is interconnected fully by a switch matrix FastCONNECT.Each FB provides the FPGA (Field Programmable Gate Array) with 36 inputs and 18 outputs; IOB then provides the buffering of device input and output; The FastCONNECT switch matrix is linked the output of all input signals and FB the input end of FB.

Referring to Fig. 1, Fig. 2, for the present invention is connected with LCD display, the LCD display CPLD address mapping logic circuit of LCD display interface requirement design, the address mapping logic circuit design is at functional block FB4.

Address mapping logic circuit with the CPLD design mainly is made up of gate circuit, address latch, address decoding, driving output several sections.The gate circuit input end connects the read-write pin of microcontroller, and output terminal connects the clock pin of LCD display, realizes the control input; The read-write pin of microcontroller links to each other by the read-write pin of address decoder LCD display, thereby the P0 mouth of microcontroller is connected the structure of realizing data bus with the D0-D7 of LCD display, 16 of microcontroller address buss are to realize being connected with LCD display through address latch, address decoding, driving output in the programmable logic device (PLD), output pin connects XC9572XL device drive output (itself possesses device, and figure slightly).

Each functional block FB by 18 independently macroelement form, each macroelement can be realized the function of a combinational circuit or register.Can bypass (this register is left in the basket) in when design, thus macroelement is only used as combinational logic, the register of macroelement can be configured to d type flip flop or T trigger, and we are configured to d type flip flop as latch, and clock is as the control input.And, in a functional block FB, realize latch like this, the code translator function latch output enable decoding input.

LCD display generally adopts multidigit to show because in, serial integrated circuit circuit when driving the multidigit LCD display is more loaded down with trivial details on a small scale, so large scale integrated circuit multidigit LCD display module application is more extensive.Present embodiment is selected the LCD module of the fluffy display technique far away of the smart electricity in representative Beijing company limited for use, and its series of products have multiple: have by the liquid crystalline type classification: TN, STN type; Have by the driving voltage classification: LV, HV; Have by selection sort backlight: LED EL.

The interface that MDLS character type LCD display is connected with single-chip microcomputer as shown in Figure 1, microcontroller adopts most widely used MCS51 and compatible single-chip microcomputer, interface is suitable for TN, the serial various products of STN type MDLS.

The controller of MDLS series module mostly is HD44780 and compatible circuit thereof, and in fact display module and being connected of microcontroller be exactly HD44780 and being connected of microcontroller.Operation has to HD44780: determine working method, understand duty and output display message, so the HD44780 operation has the reading and writing operation, exchange message has command word, data word, and the interface of HD44780 process (CPLD address mapping logic circuit) must be connected with the micro controller system bus.Pin function according to module connects, and is connected with the micro controller system bus except that need are considered pin function, also need consider sequential coordination question.

Table 1 is the pin function definition of MDLS series LCD MODULE

Table 1 pin function

Pin number	Symbol	State	Function
					1	Vss		Power supply ground
2	Vdd		The 5V logic
				3	V0		Power supply liquid crystal drive power supply
4	RS	Input	Register selects 1: data 0: instruction
				5	R/W	Input	Read-write operation selects 1: read 0: write
6	E	Input	Enable signal (MDLS40466 symbol NC)
				7	DB0	Ternary	Data bus (LSB)
8	DB1	Ternary	Data bus
				9	DB2	Ternary	Data bus
10	DB3	Ternary	Data bus
				11	DB4	Ternary	Data bus
12	DB5	Ternary	Data bus
				13	DB6	Ternary	Data bus
14	DB7	Ternary	Data bus (MSB)

Table 2 is the signal truth table

Table 2 signal truth table

RS	R/W	E	Function
				0	0	Negative edge	The write command code
0	1	High level	Read busy sign and AC value
				1	0	Negative edge	Write data
1	1	High level	Read data

HD44780 writes sequential chart

The table write cycles

Project	Symbol	Minimum value	Maximal value	Unit
					Enable the cycle	TcycE	1000		ns
The enabling pulse width	Pweh	450		ns
					Enable lifting time	Ter，Tef		25	ns
Address Time Created	Tas	140		ns
					Low address hold time	Tah	10		ns
Data setup time	Tdsw	195		ns
					Data hold time	Th	10		ns

HD44780 reads sequential chart

The table read operation cycle

Project	Symbol	Minimum value	Maximal value	Unit
					Enable the cycle	TcycE	1000		ns
The enabling pulse width	Pweh	450		ns
					Enable lifting time	Ter，Tef		25	ns
Address Time Created	Tas	140		ns
					Low address hold time	Tah	10		ns
The data delay time	Tddr		320	ns
					Data hold time	Tdhr	10		ns

Referring to Fig. 3, Fig. 4, the reading and writing of HD44780 operation is united realization by R/W signal and enable signal E.In the write operation process, HD44780 requires after the E signal ended, and the data on the data line will keep the above time of 10ns, and MCS51 P0 mouth will have the data hold time of 58ns (calculating with the 12MHz crystal oscillator) after/WR signal ended, be enough to meet the demands.Under the read operation situation, MCS51 read signal pulse width reaches 400ns, and greater than maximum data delay time (Tddr) 320ns of HD44780, it is feasible that the sequential of the two cooperates.After analyzing above-mentioned situation, this patent does not adopt the conventional interface pin signal method that connects one to one, and the operation of the corresponding mapping address that order and data write operation all have been reduced to connects interface and programming obtains simplification.

Thereby the P0 mouth of interface schema explanation microcontroller is connected the structure of realizing data bus with D0-D7, and 16 of microcontroller address buss are to be connected the structure of realizing address bus with Liquid Crystal Module through CPLD address mapping logic circuit.

By interface schema present embodiment signal combination as can be known, the characteristic that circuit is formed: R/W is selected in read-write operation such as read/write operation to the instruction and data of Liquid Crystal Module; The operation of the corresponding mapping address that register selection RS (DATA) has been reduced to, enable signal E (CLK) is produced by the CPLD logical circuit when read-write.

Address explanation to the Liquid Crystal Module operation is as shown in table 3

Table 3 Liquid Crystal Module operation address

Operation address	CS2	R/W	RS	Function
					***0H	0	0	0	Write command
***1H	0	0	1	Write data
					***2H	0	1	0	Read busy sign and AC value
***3H	0	1	1	Read data

Embodiment 2

LED (Light Emitting Diode) light emitting diode indicator is a kind of device that produces visible light on the light emitting diode that is added in when impressed voltage, have that volume is little, in light weight, operating voltage is low, stable, the life-span long, short (generally being no more than 0.1 μ S), luminous even, clear, brightness advantages of higher of response time, compare with LCD, be more suitable in the dark environment of light, using.Its major defect is that working current is bigger.General chip can not directly drive, Xilinx XC9500 driving load capacity is strong, and the load current of each input/output end port can reach 24mA, and directly driving LED shows, common light-emitting diode display has: LED charactron and LED light are all having use aspect the control demonstration.

Different with LCD display, the size of light-emitting diode display, figure place has multiple choices, and the relative LCD of circuit is simple, does not generally adopt LED display module form, like this, selects the display interface scheme just to have multiple.The display display interface can be divided into the static two kinds of display modes that show and dynamically show by type of drive, whether be with code translator can be divided into decoding and two kinds of video data modes of non-decoding by the nixie display interface, microcontroller adopts the parallel transfer mode usually to the mode that display interface device transmits data.

Decoding video data mode need be deciphered/chip for driving, and the character display dullness, and advantage software is simple, and non-decoding video data mode needs software decoding.Display is static when showing, during the change video data, each display all is in the energising show state, each display energising dutycycle is about 100%.The static advantage that shows is to show to stablize the brightness height; Shortcoming is that to take hardware circuit (as I/O mouth, driver etc.) many.Dynamically the scanning that shows can be finished by scm software or special hardware; When dynamically showing, N display takies a video data driver altogether, and each display energising dutycycle time is 1/N to the maximum.Change and can change display brightness conduction time, dynamically the advantage that shows is to save hardware circuit (as I/O mouth, driver etc.); It is many that shortcoming takies CPU time when being the employing software scans, will increase hardware cost during as the employing hardware scanning.

LED demonstration/the keyboard interface of current trend, adopting universal programmable chips design light-emitting diode display interface generally is dynamic demonstration, non-decoding and parallel transfer video data load mode, interface also needs chip for driving

Referring to Fig. 5, Fig. 6, for keyboard of the present invention is connected with light-emitting diode display, microcontroller connects through CPLD logical and light-emitting diode display, adopt dynamically demonstration, non-decoding and serial transfer video data load mode, can connect 8 eight sections LED nixie displaies or 64 LED light, only illustrated among the figure 4 eight sections positive LED nixie display and 8 LED light altogether to increase and decrease as required.Adopt serial interface mode, it only takies 2 I/O mouths of system, makes data lead-in wire DK DATA for one, and another saves micro controller I/O mouth as clock cable DK CLK.Wherein DK Q0～DK Q7 is the segment encode line for the light-emitting diode display data line, and BIT0～BIT3 is the bit code sweep trace of light-emitting diode display, links to each other with microcontroller P1 mouth.Send sweep signal by them, take the decoding/driving of PCLD logic, save micro controller I/O mouth and driver.

The principle that serial mode LED dynamically shows at first sends the 1st 8 bit data with serial mode to the light-emitting diode display FPDP, and this moment is because BIT0 is a high level and other mouthfuls all be low level, so has only the LED1 charactron to show this number.Can send the 2nd data like this, should to make its corresponding bit code equally be high level and guarantee that other positions are for low level.The rest may be inferred, and each display is scanned, and the display timesharing takes turns to operate.Though have only a display to show, because people's persistence of vision phenomenon can feel that still all displays all show at the same time at every turn.Its advantage is: take less I/O mouth.

In the light-emitting diode display interface, sealing in and going out data DK Q0～DK Q7 double as is the keyboard scan line, and KEY0, KEY1 are keyboard data loopback line, increases the KEY line and can increase the keyboard number.The keyboard that uses in the microcontroller generally is a nonencoded keyboard, and less comparatively speaking because of button, so claim keypad again, Fig. 2 has 16 buttons, forms row-column configuration, during keyboard scan, exports full low level from DK Q0～DK Q7 earlier, detects KEY.If the KEY line is high level then represents not have the key closure; If KEY equals 0, expression has key to press, and then from DK Q0～DK Q7 output low level successively, detects KEY.If the KEY line is high level then represents not have the key closure; If KEY equals 0, the data on DK Q0～DK Q7 are just obtained the key assignments of each key correspondence through simple process.

By interface schema this patent signal combination as can be known, the characteristic that circuit is formed: adopt serial interface mode, it only takies 2 I/O mouths of system, saves micro controller I/O mouth.Q0～DK Q7 is that LED is the segment encode line as the display data line for string and conversion output DK, PCLD

Decoding output BIT0～BIT3 is as the bit code sweep trace of light-emitting diode display, and sealing in and going out data DK Q0～DK Q7 double as is the keyboard scan line, reduces lead-in wire.PCLD I/O piece IOB drives connection, saves driver chip.

More than show and described ultimate principle of the present invention and principal character and advantage of the present invention.The technician of the industry should understand; the present invention is not restricted to the described embodiments; that describes in the foregoing description and the instructions just illustrates principle of the present invention; without departing from the spirit and scope of the present invention; the present invention also has various changes and modifications, and these changes and improvements all fall in the claimed scope of the invention.The claimed scope of the present invention is defined by appending claims and equivalent thereof.

Claims (7)

1. the nonencoded keyboard of a watercraft embedded micro-controller and display interface device comprise the logical circuit that programmable logic device (PLD) constitutes, and it is characterized in that: the input end of described logical circuit links to each other with display with microcontroller respectively with output terminal.

2. the nonencoded keyboard of watercraft embedded micro-controller as claimed in claim 1 and display interface device is characterized in that: described programmable logic device (PLD) constitutes nonencoded keyboard and the display interface device that is fit to watercraft embedded micro-controller by programmed.

3. the nonencoded keyboard of watercraft embedded micro-controller as claimed in claim 1 and display interface device, it is characterized in that: described display comprises LCD display and/or light-emitting diode display, and described logical circuit comprises the light-emitting diode display keyboard logic circuit that LCD display address mapping logic circuit that keyboard is connected with LCD display and keyboard are connected with light-emitting diode display.

4. the nonencoded keyboard of watercraft embedded micro-controller as claimed in claim 3 and display interface device, it is characterized in that: described LCD display address mapping logic circuit is made of gate circuit, address latch, address decoder and driving output circuit, described gate circuit input end connects the read-write pin of microcontroller, output terminal connects the clock pin of LCD display, realizes the control input; The read-write pin of microcontroller links to each other with the read-write pin of LCD display by address decoder, thereby the P0 mouth of microcontroller is connected the structure of realizing data bus with the D0-D7 of LCD display, and 16 of microcontroller address buss are to realize being connected with LCD display through address latch, address decoder, driving output circuit in the programmable logic device (PLD).

5. the nonencoded keyboard of watercraft embedded micro-controller as claimed in claim 3 and display interface device, it is characterized in that: described LCD display address mapping logic circuit can be made of the CPLD functional block, each functional block by 18 independently macroelement form, each macroelement can be realized the function of a combinational circuit or register.

6. the nonencoded keyboard of watercraft embedded micro-controller as claimed in claim 4 and display interface device, it is characterized in that: described address latch is a d type flip flop.

7. the nonencoded keyboard of watercraft embedded micro-controller as claimed in claim 3 and display interface device, it is characterized in that: described light-emitting diode display keyboard logic circuit comprises serial-in parallel-out register, code translator and three-state buffer, code translator is connected with the microcontroller serial line interface, one of two pins is as data lead, another is as clock cable, and the output pin of code translator connects light-emitting diode display segment encode line; The bit code sweep trace of light-emitting diode display connects the output port of microcontroller by three-state buffer.

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