lcd液晶顯示器控制的原理畢業論文-資料下載頁

　　

【正文】 the newest revision (1969), before then, has RS232B, RS232A. . It stipulates the tie cable and the machinery, the electrical specification, the signal function and the transmission process. The monly used physical standard also has EIAamp。0。 RS232C, EIAamp。0。 RS422A, EIAamp。0。 RS423A, EIAamp。0。 RS485. Here only introduces EIAamp。0。 RS232C (. 232, RS232). For example, in IBM PC machine on COM1, the COM2 connection, is the RS232C connection at present. 1. electrical specification EIARS232C to the electric appliance characteristic, the logic level and each kind of holding wire function has made the stipulation. on TxD and RxD: Logical 1(MARK)=3V~15V logical 0(SPACE)=+3~+15V on pilot wires and so on RTS, CTS, DSR, DTR and DCD: signal effective (connection, ON condition, positive voltage) =+3V~+15V signal invalid (separation, OFF condition, negative voltage) =3V~15V The above stipulation showed the RS323C standard to the logic level definition. Regarding data (information code): Logic “1” (mark) the level is lower than 3V, logic “0” (blank) the level considers language +3V。 Regarding control signal。 The connection condition (ON) is the signal effective level is higher than +3V, disconnect state (OFF) is the signal invalid level is lower than 3V, is also when transmission level39。s absolute value is bigger than 3V, the electric circuit may inspect effectively, is situated between between the 3~+3V voltage to be insignificant, is lower than 15V or is higher than +15V the voltage also to think insignificantly, therefore, time practical work, should guarantee the level between 177。 (3~15)V. EIARS232C and TTL transformation: EIARS232C is expresses the logical condition with the positive and negative voltage, with TTL by height level expression logic The condition stipulation is different. Therefore, for can with the puter connection or the terminal TTL ponent connection, must carries on the level and the logical relation transformation in EIARS232C and between the TTL electric circuit. Realizes this kind of transformation method available discrete ponent, also available integrated circuit chip. At present widely uses the integrated circuit to transform the ponent, like MC1488, the SN75150 chip may plete the TTL level to the EIA level transformation, but MC1489, SN75154 may realize the EIA level to the TTL level transformation. The MAX232 chip might plete TTL←→EIA the bidirectional level switch, Figure 1 has demonstrated 1488 and 1489 internal structures and the pin. The MC1488 pin (2), (4,5), (9,10) and (12,13) meet the TTL input. Pin 3, 6, 8, 11 output termination EIARS232C. MC1498 14 1, 4, 10, 13 feet meet the EIA input, but 3, 6, 8, 11 feet meet the TTL output. Concrete connection method as shown in Figure 2. In the chart left side is in microputer serial interface electric circuit39。s main chip UART, it is the TTL ponent, right side is the EIARS232C coupling, requests the EIA high voltage. Therefore, RS232C all outputs, the input signal must separately after MC1488 and the MC1498 switch, after carrying on the level switch, can deliver the coupling to e up or feed from the coupling. 2, coupling39。s physical characteristics: Coupling: Because RS232C has not defined coupling39。s physical property, therefore, presented DB25, DB15 and the DB9 each type coupling, its pin39。s definition is also various. Below introduces two kind of couplings separately. (1) DB25: PC and XT machine uses the DB25 coupling. The DB25 coupling has defined 25 holding wires, divides into 4 groups: ①Asynchronous munication 9 voltage signal (including signal SG) 2,3,4,5,6,7,8,20,22 ②20mA electric current link signal 9 (12,13,14,15,16,17,19,23,24) ③Spatial 6 (9,10,11,18,21,25) ④The protectorate (PE) 1, takes the equipment ground terminal (1 foot) The DB25 coupling39。s contour and holding wire assignment as shown in Figure 3. The attention, 20mA electric current link signal only IBM PC and IBM PC/XT machine provide, after AT machine and, has not supported. cable length: When the correspondence speed is lower than 20kb/s, the RS232C direct connection39。s maximum physical distance is 15m (50 feet). The maximum direct transmission distance explained: RS232C standing operating procedure, if does not use MODEM, in the element distortion is smaller than in 4% situations, between DTE and DCE the maximum transmitting range is 15m (50 feet). Obviously this maximum distance is in the element distortion is smaller than under 4% premises gives. In order to guarantee that the element distortion is smaller than 4% requests, the interface standard stipulated in the electrical specification, driver39。s load capacitance should be smaller than 2500pF.附錄3 液晶顯示模塊SMC1602A字庫附錄4 軟件程序includeincludedefine uchar unsigned char define uint unsigned int sbit lcden=P2^0。//使能端E為P1^2口sbit lcdrw=P2^1。//讀/寫選擇端RW為P1^1口sbit lcdrs=P2^2。//數據/指令選擇端RS為P1^0口uchar const table[]=Good Good Study 。uchar const table1[]=Day Day Up ! 。 void delay(uint z)。//延時子函數聲明void write_(uchar )。//寫指令子函數聲明void write_date(uchar date)。//寫數據子函數聲明void init()。//LCD初始化子函數聲明void main(){ uint i。init()。 delay(600)。//停3秒 write_(0x80+0x10)。//顯示第1行 delay(3)。 for(i=0。i16。i++)//第一行的存儲單元 { write_date(table[i])。 delay(3)。 } write_(0x80+0x53)。//顯示第2行 delay(3)。 for(i=0。i14。i++)//第二行的存儲單元 { write_date(table1[i])。 delay(3)。 } for(i=0。i24。i++) //左移16位 { write_(0x1c)。//1c delay(300)。 } delay(3000)。//停3秒 write_(0x08)。//閃爍 delay(300)。 write_(0x0c)。 delay(300)。 write_(0x08)。 delay(300)。 write_(0x0c)。 delay(300)。 write_(0x08)。 delay(300)。 write_(0x0c)。 delay(300)。 delay(3000)。//停3秒 write_(0x01)。 write_(0x80+0x10)。 //顯示第1行 delay(3)。 for(i=0。i22。i++) { write_date(table[i])。 delay(3)。 } write_(0x80+0x53)。 //顯示第2行 delay(3)。 for(i=0。i11。i++) { write_date(table1[i])