lcm.c

IO

//Lcm.c
//
//Body: HT48C30-1
//Mask option
//BZ/BZB : All Disable
//the others use the default value

#include <ht48c30-1.h>

#pragma vector isr_4 @ 0x4
#pragma vector isr_8 @ 0x8
#pragma vector isr_c @ 0xc

//ISR for safequard
void isr_4(){} // external ISR
void isr_8(){} // timer/event 0
void isr_c(){} // timer/event 1

//initialize registers for safeguard
void safeguard_init(){
        _intc = 0;
        _tmrc = 0;
        _tmr = 0;
        _pac = 0xff; //input mode
        _pbc = 0xff;
        _pcc = 0xff;
}

//#define FOUR_BIT
//#define ONE_LINE

//for DV-16100NRB
// port B : LCM data port
// port C : LCM control port
#define LCM_CLS         0x1
#define CURSOR_HOME     0x2
#define CURSOR_SR       0x14
#define CURSOR_SL       0x10
#define INCDD_CG_SHF_C  0x6
#define TURN_ON_DISP    0xf
#define LCD_ON_CSR_OFF  0xc

#define LCM_DATA        _pb
#define LCM_DATA_CTRL   _pbc
#define LCM_CTRL        _pc
#define LCM_CTRL_CTRL   _pcc

#define LCM_CTRL_E      _pc0
#define LCM_CTRL_RW     _pc1
#define LCM_CTRL_RS     _pc2

#define WRITE(a)        { \
LCM_DATA = (a); \
LCM_CTRL_E = 1; \
LCM_CTRL_E = 0;}

const unsigned char msg[16] = "HOLTEK 8 bit MCU";

void mydelay(unsigned char ct);
void LCM_initialize();
void send_cmd(unsigned char);
void write_char(unsigned char);
void busy_check(void);
void lcm_delay(void);

void main(){
        unsigned int i;

        safeguard_init();
        LCM_initialize();

        while(1){
                send_cmd(LCM_CLS);
                mydelay(2);
                send_cmd(CURSOR_HOME);
                for(i = 0; i<sizeof(msg); i++){
                        if (i == 8) 
                                send_cmd(0xc0); //move cursor to 2nd line
                        write_char(msg[i]);     //(1st line:00h~, 2nd line:40h~)
                }
                send_cmd(LCD_ON_CSR_OFF);
                mydelay(5);
        }
}

void mydelay(unsigned char ct){
        while(ct--) _delay(65535);
}

void LCM_initialize(){
        LCM_DATA_CTRL = 0;      //setup LCM data port as output port
        LCM_CTRL_CTRL = 0;      //setup LCM control port as output port
        LCM_DATA = 0;           //clear LCM data port
        LCM_CTRL = 0;           //clear LCM control port

#ifdef FOUR_BIT
        WRITE(0x20); //4 bit mode
#else
        WRITE(0x30); //8 bit mode
#endif

        //According to the data for the HD44780, there needs to be at
        //least 4.5 ms delay between each program.
        mydelay(1);

#ifdef FOUR_BIT
#ifdef ONE_LINE
        WRITE(0x20); //4-bit 1-line
#else
        WRITE(0x28); //4-bit 2-line
#endif
#else
#ifdef ONE_LINE
        WRITE(0x30); //8-bit 1-line
#else
        WRITE(0x38); //8-bit 2-line
#endif
#endif

#ifdef FOUR_BIT
        WRITE(0x80); //4-bit high nibble (2nd pass)
#endif
        send_cmd(LCM_CLS);                      //clean display
        send_cmd(TURN_ON_DISP);         //turn on display
        send_cmd(INCDD_CG_SHF_C);       //auto increment mode
                                                                //cursor left and DD RAM address+1
}


// send command to LCM
void send_cmd(unsigned char c){
#ifdef FOUR_BIT
        unsigned char tmp;
        tmp = c << 4;
        c &= (unsigned char)0xf0;
#endif
        busy_check();
        LCM_DATA = c;
        LCM_CTRL_RW = 0;
        LCM_CTRL_RS = 0;
        LCM_CTRL_E = 1;
        LCM_CTRL_E = 0;
#ifdef FOUR_BIT
        WRITE(tmp);
#endif
}

// write character to LCM
void write_char(unsigned char c){
#ifdef FOUR_BIT
        unsigned char tmp;
        tmp = c<<4;
        c &= (unsigned char)0xf0;
#endif
        busy_check();
        LCM_DATA = c;
        LCM_CTRL_RW = 0;
        LCM_CTRL_RS = 1;
        LCM_CTRL_E = 1;
        LCM_CTRL_E = 0;
#ifdef FOUR_BIT
        WRITE(tmp);
#endif
}

// Wait until the busy flag is not busy
void busy_check(void){
        unsigned char val, tmp;
        do{
                LCM_CTRL_E = 0;
                LCM_DATA_CTRL = 0xff;
                LCM_CTRL_RS = 0;
                LCM_CTRL_RW = 1;
                LCM_CTRL_E = 1;
                val = LCM_DATA;
                LCM_CTRL_E = 0;
#ifdef FOUR_BIT
                tmp = val & (unsigned char)0xf0;//4-bit high nibble
                LCM_CTRL_E = 1;                 //pulse high
                val = LCM_DATA;                 //4-bit low nibble (2nd pass)
                LCM_CTRL_E = 0;                 //pulse low
                val = (val>>4) | tmp;           //combine 2 pass
#endif
        }while(val & (unsigned char)0x80);
        LCM_CTRL_RW = 0;
        LCM_DATA_CTRL = 0;      //LCM not busy, then set LCM data
                                //bus to input port
}