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1．LCD驅動器1621
HT1621為128（32×4）段LCD驅動器。它可設置為1/2或1/3偏置且通過S/W配置設置為2，3或4個共用的LCD驅動器。這使得HT1621適于多LCD應用。LCD驅動時鐘
圖5.6 HT1621功能框圖 從系統時鐘內產生，一般為256KHZ。圖5.6為HT1621功能框圖 2．EM78X56與HT1621接口 EM78X56與HT1621接口只須四條線。CS線用以初始化串行接口電路且終止EM78X56與HT1621的通信。若CS=1，EM78X56及HT1621間發送的命令首先被禁止即而進行初始化。在模式命令或模式轉換發出前，需要一高電平脈沖以初始化HT1621的串行接口，數據的讀/寫及命令的寫人必須通過數據線。RD為輸入，RAM內的數據在RD信號的下降沿同步送出至數據線上。這使EM78X56可以在RD信號的升沿及下一個下降沿到來期間讀人正確的數據。WR為寫輸入，數據線上的數據、地址及命令將在WR信號上升寫入HT1621。一條可選擇的IRQ線也可用作EM78X56及HT1621間的接口。 1.
讀／寫命令時序控制及命令集 | Command Code | D/C | Function | READ | 110 a5 a4 a3 a2 a1 a0 d0 d1 d2 d3 | D | Read data in the RAM | WRITE | 101 a5 a4 a3 a2 a1 a0 d0 d1 d2 d3 | D | Write data to the RAM | READ MODIFY WRITE | 101 a5 a4 a3 a2 a1 a0 d0 d1 d2 d3 | D | READ and WRITE to RAM | SYS DIS | 100000000000X | C | Turn off bth system oscillator And LCD blas generator | SYS EN | 100000000001X | C | Turn on system oscillator | LCD OFF | 100000000010X | C | Turn off LCD blas generator | LCD ON | 100000000011X | C | Turn on LCD bias generator | XTAL 32K | 1000000101XXX | C | System clock source,crystal oscillator | BIAS 1/2 | 1000010abX0X | C | LCD 1/2 bias sption ab=00:2 commons option ab=01:3 commons option ab=10:4 commons option | BIAS 1/3 | 1000010abX1X | C | LCD 1/2 bias sption ab=00:2 commons option ab=01:3 commons option ab=10:4 commons option |
4. 應用電路 圖 5.7 HT1621應用框圖 5. 編程示例
R1 EQU 0X01 R2 EQU 0X02 R3 EQU 0X03 IOC5 EQU 0X05 IOC6 EQU 0X06 PORT5 EQU 0X05 PORT6 EQU 0X06 IOCB EQU 0X0B IOCC EQU 0X0C IOCD EQU 0X0D IOCE EQU 0X0E IOCF EQU 0X0F S1 EQU 0X10 S2 EQU 0X11 S3 EQU 0X12 S4 EQU 0X13 S5 EQU 0X14 S6 EQU 0X15 S7 EQU 0X16 S8 EQU 0X17 S8S7 EQU 0X18 S9 EQU 0X19 S10 EQU 0X1A COMMAND EQU 0X1B R_LOOP EQU 0X1C S_LOOP EQU 0X1D SEG0 EQU 0X1E SEG1 EQU 0X1F SEG2 EQU 0X20 SEG3 EQU 0X21 SEG4 EQU 0X22 SEG5 EQU 0X23 SEG6 EQU 0X24 SEG7 EQU 0X25 SEG8 EQU 0X26 SEG9 EQU 0X27 SEG10 EQU 0X28 LCD_MAP EQU 0X29 LCDRAM EQU 0X2A KEY2 EQU 0X2B KEY7 EQU 0X2C KEY_SX EQU 0X2D LP_CNT0 EQU 0X2E LP_CNT1 EQU 0X2F
ORG 0X000 JMP MAIN NOP MAIN: CLRA ;P50-P53 SET TO OUTPUT IOW IOC5 IOW IOCE MOV A,@0B11110000 ;P60-P63 SET TO OUTPUT IOW IOC6 ;P64-P67 SET TO INPUT MOV A,@0X0F MOV PORT5,A ;P50-P53 RESET TO 1 CLR PORT6 ;P60-P63 RESET TO 0 BC PORT5,0 ;RESET 1621 INTERFACE BS PORT5,0 BC PORT5,0 BS PORT5,0 ;P50 SET TO 1,/CS=1 MOV A,@0B11100011 ;COMMAND TNORMAL MOV COMMAND,A CALL C_WRITE MOV A,@0B10000000 ;COMMAND /IRQ DIS MOV COMMAND,A CALL C_WRITE MOV A,@0B00010100 ;COMMAND XTAL32K MOV COMMAND,A CALL C_WRITE MOV A,@0B00101001 ;COMMAND BIAS1/3,4 COM MOV COMMAND,A CALL C_WRITE MOV A,@0B00001000 ;COMMAND TONE OFF MOV COMMAND,A CALL C_WRITE MOV A,@0B00000101 ;COMMAND WDT DIS MOV COMMAND,A CALL C_WRITE MOV A,@0B00000100 ;COMMAND TIMER DIS MOV COMMAND,A CALL C_WRITE MOV A,@0B00000001 ;COMMAND SYS_EN MOV COMMAND,A CALL C_WRITE MOV A,@0B00000011 ;COMMAND LCD_ON MOV COMMAND,A CALL C_WRITE MOV A,@0X0FF ;LCD MAP SET TO 1 MOV SEG0,A MOV SEG2,A MOV SEG3,A MOV SEG4,A MOV SEG5,A MOV SEG6,A MOV SEG7,A MOV SEG8,A MOV SEG9,A MOV SEG10,A CLR LCD_MAP ;FIRST MAP ADD IS 0 CALL LCD_WRITE ;DISPLAY ALL SEGS (BREAK): LCD_OFF: CLR COMMAND ;TURN OFF LCD SYSTEM CALL C_WRITE C_WRITE: MOV A,@0X08 MOV R_LOOP,A BS PORT5,2 ;/WR=1 BC PORT5,0 ;/CS=0 BC PORT5,2 ;/WR=0 BS PORT5,3 ;DATA=1 BS PORT5,2 ;/WR=1 BC PORT5,2 ;/WR=0 BC PORT5,3 ;DATA=0 BS PORT5,2 ;/WR=1 BC PORT5,2 ;/WR=0 BC PORT5,3 ;DATA=0 BS PORT5,2 ;/WR=1 BC PORT5,2 ;/WR=0 C8_C1_WRITE: JBC COMMAND,7 ;COMMAND,7=0 JMP SET_DATA_1 BC PORT5,3 ;DATA=0 JMP NEXT_1 SET_DATA_1: BS PORT5,3 ;DATA=1 NEXT_1: RLC COMMAND BS PORT5,2 ;/WR=1 BC PORT5,2 ;/WR=0 DJZ R_LOOP JMP C8_C1_WRITE BC PORT5,3 ;DATA=0 BS PORT5,2 ;/WR=1 BS PORT5,0 ;/CS=1 RET LCD_WRITE: BS PORT5,2 ;/WR=1 BC PORT5,0 ;/CS=0 BC PORT5,2 ;/WR=0 BS PORT5,3 ;DATA=1 BS PORT5,2 ;/WR=1 BC PORT5,2 ;/WR=0 BC PORT5,3 ;DATA=0 BS PORT5,2 ;/WR=1 BC PORT5,2 ;/WR=0 BS PORT5,3 ;DATA=1 BS PORT5,2 ;/WR=1 BC PORT5,2 ;/WR=0 ;WRITE THE LCD MEMORY ADD 00 BC PORT5,3 ;DATA=0, 1 BS PORT5,2 ;/WR=1 BC PORT5,2 ;/WR=0 ;DATA=0, 2 BS PORT5,2 ;/WR=1 BC PORT5,2 ;/WR=0 ;DATA=0, 3 BS PORT5,2 ;/WR=1 BC PORT5,2 ;/WR=0 ;DATA=0, 4 BS PORT5,2 ;/WR=1 BC PORT5,2 ;/WR=0 ;DATA=0, 5 BS PORT5,2 ;/WR=1 BC PORT5,2 ;/WR=0 ;DATA=0, 6 BS PORT5,2 ;/WR=1 MOV A,SEG0 MOV LCDRAM,A ;SEG0 CALL LCDDATA_W MOV A,SEG1 MOV LCDRAM,A ;SEG1 CALL LCDDATA_W MOV A,SEG2 MOV LCDRAM,A ;SEG2 CALL LCDDATA_W MOV A,SEG3 MOV LCDRAM,A ;SEG3 CALL LCDDATA_W MOV A,SEG4 MOV LCDRAM,A ;SEG4 CALL LCDDATA_W MOV A,SEG5 MOV LCDRAM,A ;SEG5 CALL LCDDATA_W MOV A,SEG6 MOV LCDRAM,A ;SEG6 CALL LCDDATA_W MOV A,SEG7 MOV LCDRAM,A ;SEG7 CALL LCDDATA_W MOV A,SEG8 MOV LCDRAM,A ;SEG8 CALL LCDDATA_W MOV A,SEG9 MOV LCDRAM,A ;SEG9 CALL LCDDATA_W MOV A,SEG10 MOV LCDRAM,A ;SEG10 CALL LCDDATA_W BS PORT5,0 ;/CS=1 RET LCDDATA_W: MOV A,@0X04 ;RAM DATA WRITE MOV R_LOOP,A DATA_W JBC LCDRAM,0 JMP RAM_SET BC PORT5,3 ;DATA=0 JMP NEXT_3 RAM_SET: BS PORT5,3 ;DATA=1 NEXT_3: RRC LCDRAM BS PORT5,2 ;/WR=1 BC PORT5,2 ;/WR=0 DJZ R_LOOP JMP DATA_W RET EOP 在EM78系列單片機內部沒有異步串行口，所以必須用軟件來完成這個工作。在很多實際應用中，我們已經采用了軟件實現RS232標準的異步串行通信，結果證明工作非常穩定可靠。用軟件完成串行通信，降低了芯片的硬件成本。 下面給出RS232的發送和接收的程序和流程，供讀者參考。 圖5.8 RS232的發送和接收流程 程序清單如下：
；定義 STATUS EQU 3 P5 EQU 5 P6 EQU 0X06
BUFFER EQU 0X11 COUNT EQU 0X12 BITNUM EQU 8 ;每字節數據為8位 ORG 0 JMP MAIN ;主程序 MAIN: MOV A,@0X40 ；置P6.5為輸出口，P6.6為輸入口 IOW P6 CLR BYTE MOV A,@BITNUM MOV COUNT,A ；傳送數據為每字節8位 ；以下為接收 TEST: JBC P6,6 ；檢測是否收到起始位 JMP TEST ；未測到 CALL DELAY ；測到起始位，下面準備接收 CALL DELAY ；延時 START: JBC P6,6 BS BYTE,7 ；收到高電平 JBS P6,6 BC BYTE,7 ；收到低電平 DJZ COUNT JMP L1 ；一個字節未收完，繼續收下一位 CALL DELAY JMP TRANSMIT ；一個字節收完，準備發送 L1: RRC BYTE CALL DELAY JMP START ；以下為發送 TRANSMIT:
MOV COUNT,A BEGIN: BC P6,5 ；發送起始位 CALL DELAY1 ；延時 L2: RRC BYTE ；發送一位數據 JBC STATUS,C BS P6,5 JBS STATUS,C BC P6,5 CALL DELAY1 ；延時 DJZ COUNT ；一個字節發送完否？ JMP L2 ；否，繼續發送下一位 BS P6,5 ；是 CALL DELAY1 JMP TEST ；繼續循環 ；延時子程序 DELAY: MOV A,@23 MOV BUFFER,A LOOP: DJZ BUFFER JMP LOOP RET DELAY1: MOV A,@30 MOV BUFFER,A LOOP1: DJZ BUFFER JMP LOOP1 RET
I2C串行總線具有占用I/O口少，控制方式簡單，信號傳輸速度快，配套功能芯片種類多的優點，非常適用于單片機系統設計中，I2C串行總線由兩根線構成：數據線（SDA），時鐘線（SCL）,其數據傳輸過程在很多書中都有介紹，這里不做專門說明。下面以24CXX系列SEEPROM為例介紹EM78系列單片機如何設計I2C總線接口。 1．電路設計電路連接如圖5.9所示： 圖 5.9 EM78XX單片機與24CXX電路連接 2.程序流程圖 程序流程圖如圖5.10所示。 SEEPROM 寫入數據傳送格式如下： START | 從地址 | 0 | A | 地址字節 | A | 數據字節1 | A | … | 數據字節N | A | STOP |
A為從設備的確認位。 SEEPROM 讀出數據傳送格式如下：（A為確認位。） START | 從地址 | 0 | A | 地址字節 | A | START | 從地址 | 1 | A | 數據字節 | A | 。。。 | 最后字節 | STOP |
圖 5.10 程序流程圖 3．參考例程 ;***************************************************************************** ;** EM78單片機與24Cxx / 85Cxx 串行CMOS EEPROM接口I2C總線讀/寫的程序 ;** （所有時隙均基于2MHZ晶體震蕩器頻率） ;***************************************************************************** ; 存儲器定義 PC EQU 2 ; Program counter STAT EQU 3 ; EM78 status byte FSR EQU 4 ; RAM 選擇寄存器 P5 EQU 5 ; Port A use to select device address P6 EQU 6 ; P6.7 = SDA, P6.6 = SCL ; STATUS EQU 08 ; Status register FLAG EQU 09 ; Common flag bits register EEPROM EQU 0A ; Bit buffer ERCODE EQU 0B ; Error code (to indicate bus status) ADDR EQU 10 &, nbsp; ; Address register DATAI EQU 11 ; Stored data input register DATAO EQU 12 ; Stored data output register SLAVE EQU 13 ; Device address (1010xxx0) TXBUF EQU 14 ; TX buffer RXBUF EQU 15 ; RX buffer COUNT EQU 16 , ; Bit counter TIMER0 EQU 18 ; Delay timer0 TIMER1 EQU 19 ; Delay timer1 ;----------------------------------------------------------------------------- ; 位定義 ; Status bits Z EQU 2 C EQU 0 ; FLAG Bits ERROR EQU 0 ; Error flag ; EEPROM Bits DI EQU 7 ; EEPROM input DO EQU 6 ; EEPROM output ; I2C Device Bits SDA EQU 7 ; P6.7, data in/out SCL EQU 6 ; P6.6, serial clock ;----------------------------------------------------------------------------- ; 兩線I2C - CPU 通信錯誤狀態表和子程序 ; input : W-reg = error code ; output : ERCODE = error code ; FLAG(ERROR) = 1 ; code error status mode ; ------- ------------------------------------------------------ ; 1 : SCL locked low by device (bus is still busy) ; 2 : SDA locked low by device (bus is still busy) ; 3 : No acknowledge from device (no handshake) ; 4 : SDA bus not released for master to generate STOP bit ;----------------------------------------------------------------------------- org 0x0000 JMP start ;按照錯誤狀態表識別SCL狀態和SDA數據子程序 ERR JBS FLAG,ERROR ; Remain as first error encountered MOV ERCODE,A ; Save error code BS FLAG,ERROR ; Set error flag RET ;----------------------------------------------------------------------------- ; 啟動總線通信程序 ; input : none ; output : initialize bus communication ;----------------------------------------------------------------------------- ;Generate START bit (SCL is high while SDA goes from high to low transition) ;and check status of the serial clock. BSTART MOV A,@B'00111111' ; Put SCL, SDA line in output state IOW P6 bs P6,SDA ;make sure sda is high BS P6,SCL ; Set clock high MOV A,@1 ; Ready error status code 1 JBS P6,SCL ; Locked? CALL ERR ; SCL locked low by device BC P6,SDA ; SDA goes low during SCL high NOP ; Timing adjustment NOP NOP BC P6,SCL ; Start clock train RET ;----------------------------------------------------------------------------- ; 啟動總線通信程序 ; Input : None ; Output : Bus communication, STOP condition ;----------------------------------------------------------------------------- ;Generate STOP bit (SDA goes from low to high during SCL high state) ;and check bus conditions. BSTOP MOV A,@B'00111111' ; Put SCL, SDA line in output state IOW P6 BC P6,SDA ; Return SDA to low BS P6,SCL ; Set SCL high nop nop MOV A,@1 ; Ready error code 1 JBS P6,SCL ; High? CALL ERR ; No, SCL locked low by device BS P6,SDA ; SDA goes from low to high during SCL high MOV A,@4 ; Ready error code 4 JBS P6,SDA ; High? CALL ERR ; No, SDA bus not release for STOP RET END SUB ;----------------------------------------------------------------------------- ; 從EM78 發送數據到串行EEPROM, 一位一位子程序 ; Input : None ; Output : To (DI) of serial EEPROM device ;----------------------------------------------------------------------------- BITIN MOV A,@B'10111111' ; Force SDA line as input IOW P6 BS P6,SDA ; Set SDA for input BC EEPROM,DI BS P6,SCL ; Clock high MOV A,@1 JBS P6,SCL ; Skip if SCL is high JMP BIT1 JBS FLAG,ERROR ; Remain as first error encountered MOV ERCODE,A ; Save error code BS FLAG,ERROR ; Set error flag BIT1 JBC P6,SDA ; Read SDA pin BS EEPROM,DI ; DI = 1 NOP ; Delay BC P6,SCL ; Return SCL to low RET ;----------------------------------------------------------------------------- ; 從串行EEPROM 接收數據, 一位一位子程序 ; Input : EEPROM file ; Output : From (DO) of serial EEPROM device to PIC ;----------------------------------------------------------------------------- BITOUT MOV A,@B'00111111' ; Set SDA, SCL as outputs IOW P6 JBS EEPROM,DO JMP BIT0 BS P6,SDA ; Output bit 0 MOV A,@2 JBC P6,SDA ; Check for error code 2 JMP CLK1 JBS FLAG,ERROR ; Remain as first error encountered MOV ERCODE,A ; Save error code BS FLAG,ERROR ; Set error flag JMP CLK1 ; SDA locked low by device BIT0 BC P6,SDA ; Output bit 0 NOP ; Delay NOP NOP CLK1： BS P6,SCL MOV A,@1 ; Error code 1 JBC P6,SCL ; SCL locked low? JMP BIT2 ; No. JBS FLAG,ERROR ; Yes. MOV ERCODE,A ; Save error code BS FLAG,ERROR ; Set error flag BIT2： NOP NOP BC P6,SCL ; Return SCL to low RET ;----------------------------------------------------------------------------- ; 接收數據子程序 ; Input : None ; Output : RXBUF = Receive 8-bit data ;----------------------------------------------------------------------------- RX MOV A,@8 ; 8 bits of data MOV COUNT,A CLR RXBUF RXLP RLC RXBUF ; Shift data to buffer JBS R3,0 ;SKPC BC RXBUF,0 ; carry ---> f(0) JBC R3,0 ;SKPNC BS RXBUF,0 CALL BITIN JBC EEPROM,DI BS RXBUF,0 ; Input bit =1 DJZ COUNT ; 8 bits? JMP RXLP BS EEPROM,DO ; Set acknowledge bit = 1 CALL BITOUT ; to STOP further input RET ;----------------------------------------------------------------------------- ; 發送數據子程序 ; Input : TXBUF ; Output : Data X'mitted to EEPROM device ;----------------------------------------------------------------------------- TX MOV A,@8 MOV COUNT,A TXLP BC EEPROM,DO ; Shift data bit out. JBC TXBUF,7 ; If shifted bit = 0, data bit = 0 BS EEPROM,DO ; Otherwise data bit = 1 CALL BITOUT ; Serial data out RLC TXBUF ; Rotate TXBUF left JBS R3,0 ; f(6) ---> f(7) BC TXBUF,0 ; f(7) ---> carry JBC R3,0 ; carry ---> f(0) BS TXBUF,0 DJZ COUNT ; 8 bits done? JMP TXLP ; No. CALL BITIN ; Read acknowledge bit MOV A,@3 JBC EEPROM,DI ; Check for acknowledgement CALL ERR ; No acknowledge from device RET ;----------------------------------------------------------------------------- ; 字節寫，寫一個字節到EEPROM器件 ; Input : DATAO= data to be written ; ADDR = destination address ; SLAVE = device address (1010xxx0) ; Output : Data written to EEPROM device ;----------------------------------------------------------------------------- WRBYTE MOVF A,SLAVE ; Get SLAVE address MOV TXBUF,A ; to TX buffer CALL BSTART ; Generate START bit CALL TX ; Output SLAVE address MOV A,ADDR ; Get WORD address MOV TXBUF,A ; into buffer CALL TX ; Output WORD address MOV A,DATAO ; Move DATA MOV TXBUF,A ; into buffer CALL TX ; Output DATA and detect acknowledgement CALL BSTOP ; Generate STOP bit JMP wrt_end ;----------------------------------------------------------------------------- ; 字節讀，從EEPROM器件讀一個字節 ; Input : ADDR = source address ; SLAVE = device address (1010xxx0) ; Output : DATAI = data read from serial EEPROM ;----------------------------------------------------------------------------- RDBYTE MOV A,SLAVE ; Move SLAVE address MOV TXBUF,A ; into buffer (R/W = 0) CALL BSTART ; Generate START bit CALL TX ; Output SLAVE address. Check ACK. MOV A,ADDR ; Get WORD address MOV TXBUF,A CALL TX ; Output WORD address. Check ACK. CALL BSTART ; START READ (if only one device is MOVF A,SLAVE ; connected to the I2C bus) MOV TXBUF,A BS TXBUF,0 ; Specify READ mode (R/W = 1) CALL TX ; Output SLAVE address CALL RX ; READ in data and acknowledge CALL BSTOP ; Generate STOP bit MOV A,RXBUF ; Save data from buffer MOV DATAI,A ; to DATAI file. JMP rd_end ;隨機讀寫測試,主程序 start： mov A,@0XAE ;set A2=A1=A0=1 mov SLAVE,A ; / mov A,@2 ;set r/w loc. = 2 mov ADDR,A ; / mov A,@55 ;write 55 to SEEPROM mov DATAO,A ; / JMP WRBYTE ;write a byte wrt_end：call delay ;wait for write operation (internal) JMP RDBYTE ;read back data rd_end mov A,@55 ;test if read xor A,DATAI ;correct? JBS STAT,Z ;yes then skip wrong JMP wrong correct JMP correct ;At 2.0Mhz, delay = approx. 3mS. Delay： clr 0X1F ;clear last location dly1： nop nop nop DJZ 0X1F ;reduce count JMP dly1 ;loop ret END |
66821730(技術支持)
