PIC C, Serial LCD Routines, CCS PCW Compiler

// Program CLCD_F84.C (CCS PCW) // // This is a collection of routines to interface with a PIC-n-LCD // or similar serial LCD capable of 9600 baud, inverted, no parity. // // 16F84 PIC-n-LCD // // RA0 (term 17) ---------------> Serin In (term 3) // // void delay_ms(long t); // delays for t ms // void delay_10us(int t); // delays for t * 10 us // void lcd_init(void); // inits PIC-n-LCD, sends 0x0c with a delay // void out_RAM_str(int *s); // output null terminated str // void lcd_hex_byte(int val); // output val in two digit hex // void lcd_dec_byte(int val, int digits); // output val in dec to significant figures specified // by digits. For example, if val is 014, specifying // digits as 3, will cause "014". Specifying digits as 2 // will cause "14" and specifying digits as 1 will cause // "4" // int num_to_char(int val); // converts val in range of // 0 - 15 to hex character // void lcd_char(int c); // outputs character c, 9600 baud, inverted // void lcd_new_line(void); // outputs 0x0d, 0x0a // copyright, Peter H. Anderson, Mecklenburg CO, VA , MD, Mar, '99 #case #include #include #include #define TxData 0 // RA.0 - output to serial LCD // LCD routines void delay_ms(long t); void delay_10us(int t); void lcd_init(void); void out_RAM_str(int *s); void lcd_hex_byte(int val); void lcd_dec_byte(int val, int digits); int num_to_char(int val); void lcd_char(int ch); void lcd_new_line(void); main() { byte s[15]; while(1) { lcd_init(); strcpy(s, "Morgan State"); // note that CONST string is copied to RAM string out_RAM_str(s); lcd_new_line(); strcpy(s, "University"); out_RAM_str(s); lcd_new_line(); lcd_hex_byte(254); // display FE

lcd_char(' '); lcd_dec_byte(192, 3); // display 192 delay_ms(500); } } void delay_10us(int t) { #asm BCF STATUS, RP0 DELAY_10US_1: CLRWDT NOP NOP NOP NOP NOP NOP DECFSZ t, F GOTO DELAY_10US_1 #endasm } void delay_ms(long t) // delays t millisecs { do { delay_10us(100); } while(--t); } int num_to_char(int val) // converts val to hex character { int ch; if (val < 10) { ch=val+'0'; } else { val=val-10; ch=val + 'A'; } return(ch); } void lcd_char(int ch) // serial output to PIC-n-LCD, 9600 baud { int n, dly; // start bit + 8 data bits #asm BCF STATUS, RP0 MOVLW 9 MOVWF n BCF STATUS, C LCD_CHAR_1: BTFSS STATUS, C BSF PORTA, TxData BTFSC STATUS, C BCF PORTA, TxData MOVLW 32 MOVWF dly

LCD_CHAR_2: DECFSZ dly, F GOTO LCD_CHAR_2 RRF ch, F DECFSZ n, F GOTO LCD_CHAR_1 BCF PORTA, TxData CLRWDT MOVLW 96 MOVWF dly LCD_CHAR_3: DECFSZ dly, F GOTO LCD_CHAR_3 CLRWDT #endasm } void lcd_init(void) // sets TxData in idle state and resets PIC-n-LCD { #asm BCF STATUS, RP0 BCF PORTA, TxData BSF STATUS, RP0 BCF TRISA, TxData BCF STATUS, RP0 #endasm lcd_char(0x0c); delay_ms(250); } void lcd_new_line(void) // outputs 0x0d, 0x0a { lcd_char(0x0d); delay_ms(10); // give the PIC-n-LCD time to perform the lcd_char(0x0a); // new line function delay_ms(10); } void out_RAM_str(int s) { while(*s) { lcd_char(*s); ++s; } } void lcd_hex_byte(int val) // displays val in hex format { int ch; ch = num_to_char((val>>4) & 0x0f); lcd_char(ch); ch = num_to_char(val&0x0f); lcd_char(ch); } void lcd_dec_byte(int val, int digits) // displays byte in decimal as either 1, 2 or 3 digits { int d; int ch; if (digits == 3)

{ d=val/100; ch=num_to_char(d); lcd_char(ch); } if (digits >1) // take the two lowest digits { val=val%100; d=val/10; ch=num_to_char(d); lcd_char(ch); } if (digits == 1) // take the least significant digit { val = val%100; } d=val % 10; ch=num_to_char(d); lcd_char(ch); }