Lcd.c description – Arizona Picdem 17 User Manual
Page 59
2001 Microchip Technology Inc.
DS39024B-page 53
LCD.C
Description
/
*******************************************************************
*
* Function Name:
ReadDataXLCD
* Return Value:
char: data byte from LCD controller
* Parameters:
void
* Description:
This routine reads a data byte from the
*
Hitachi HD44780 LCD controller. The user
*
must check to see if the LCD controller is
*
busy before calling this routine. The data
*
is read from the character generator RAM or
*
the display data RAM depending on what the
*
previous SetxxRamAddr routine was called.
*******************************************************************
*/
char ReadDataXLCD(void)
{
char data;
#ifdef BIT8
// 8-bit interface
RS_PIN = 1;
// Set the control
bits
RW_PIN = 1;
DelayFor18TCY();
E_PIN = 1;
// Clock the data out
of the LCD
DelayFor18TCY();
data = DATA_PORT;
// Read the data
E_PIN = 0;
RS_PIN = 0;
// Reset the control
bits
RW_PIN = 0;
#else
// 4-bit interface
RW_PIN = 1;
RS_PIN = 1;
DelayFor18TCY();
E_PIN = 1;
// Clock the data out
of the LCD
DelayFor18TCY();
#ifdef UPPER
// Upper nibble
interface
data = DATA_PORT&0xf0;
// Read the upper
nibble of data
#else
// Lower nibble
interface
data = (DATA_PORT<<4)&0xf0;
// read the upper
nibble of data
#endif
E_PIN = 0;
// Reset the clock
line
DelayFor18TCY();
E_PIN = 1;
// Clock the next
nibble out of the LCD
DelayFor18TCY();
#ifdef UPPER
// Upper nibble
interface
data |= (DATA_PORT>>4)&0x0f;
// Read the lower
nibble of data