PICDEM2 datasheet(41/60 Pages) MICROCHIP

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PICDEM 2 User’s Guide

DS30374D-page 36

 2001 Microchip Technology Inc.

6.1.3.

DEC_TABL Routine (kbd4bit.asm)

This routine is basically a look-up table that returns the ASCII value of the

received keypress.

6.1.4.

LCDInit Routine (lcd4bit.asm)

This routine initializes the LCD module.

Figure 6.6: LCD Initialization Routine

6.1.5.

SetupDelay Routine (lcd4bit.asm)

This routine is basically a decrementing variable loop. The variable is

initialized with a value and then decremented in a loop until it reaches zero

value. Then it jumps out of the loop and returns to the calling routine.

6.1.6.

SendCmd Routine (lcd4bit.asm)

This routine sends a command to the LCD. It splits the command into upper

and lower nibbles (4 bits) and sends these to the LCD, upper nibble first.

6.1.7.

BusyCheck Routine (lcd4bit.asm)

This routine checks the LCD busy flag. It returns only when not busy.

6.1.8.

SendChar Routine (lcd4bit.asm)

This routine sends a character to the LCD. It splits the character into upper

and lower nibbles (4 bits) and sends these to the LCD, upper nibble first.

4-bit interface, 2 lines of 5 x 7 characters

Display on, cursor on

Clear display

Set entry mode inc, no shift

Address DDRAM upper left

Send commands to LCD (SendCmd)

Return

Configure PORTA

Configure PORTD

Power-up and Set-up Sequence

(SetupDelay)

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