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/* Amrita Vishwa Vidyapeetham Amrita School of Computing, Coimbatore B.Tech Lab session– December 2022 Fifth Semester Computer Science and Engineering 19CSE303 Embedded Systems
Questions
Demonstrate UART and LCD interface using LPC2148 microcontroller. a. Display character in LCD, using UART (Tx) b. Display character in LCD. Character received from your PC keyword and send to LCD using UART (RX).
*/
include <stdio.h>
include <stdlib.h>
include <string.h>
include <lpc214x.h> //Includes LPC2148 register definitions
define PLOCK 0x00000400 // for PLL
define THRE (1<<5) // Transmit Holding Register Empty
define RDR (1<<0) // Receiver Data Ready
define MULVAL 15
define DIVADDVAL 1
define NEW_LINE 0xA // Character for new line .. analogus to '\n'
define ENTER 0xD // Ascii code for Enter
void initUART0(void); void U0Write(char data); char U0Read(void); void initClocks(void);
void setupPLL0(void); void feedSeq(void); void connectPLL0(void);
define DATA_PORT() IO0SET=(1<<16) //Function to select data port on LCD
define READ_DATA() IO0SET=(1<<17) //Function to select read operation on LCD
define EN_HI() IO0SET=(1<<18) //Function to Enable LCD
define COMMAND_PORT() IO0CLR=(1<<16) //Function to select command port on LCD
define WRITE_DATA() IO0CLR=(1<<17) //Function to select write operation on LCD
define EN_LOW() IO0CLR=(1<<18) //Function to disable LCD
void Delay(unsigned char j)
{
unsigned int i;
for(;j>0;j--)
{
for(i=0; i<60000; i++);
}
}
void Delay_Small(unsigned char j) { unsigned int i; for(;j>0;j--) { for(i=0; i<1000; i++); } }
unsigned char Busy_Wait() //This function checks the busy status of LCD { unsigned int temp=0; EN_LOW(); COMMAND_PORT(); READ_DATA();
IO0PIN&=0xFF87FFFF;
IO0DIR&=0xFF87FFFF;
IO0PIN|=0x00400000;
do{ EN_HI(); EN_LOW(); EN_HI(); EN_LOW(); temp=IO0PIN; } while((temp & 0x00400000)==0x00400000); EN_LOW(); WRITE_DATA(); IO0DIR&=0xFF80FFFF; IO0DIR|=0x007F0000; return (0); }
void LCD_Command(unsigned int data) //This function is used to send LCD commands { unsigned int temp=0; EN_LOW(); COMMAND_PORT(); WRITE_DATA();
temp=data; //IO0PIN&=0xFF87FFFF; IO0PIN&=0x00010000; IO0PIN|=(temp & 0xF0) << 15;
EN_HI(); EN_LOW();
temp=data & 0x0F; //IO0PIN&=0xFF87FFFF; IO0PIN&=0x00010000; IO0PIN|=(temp) << 19;
EN_HI(); EN_LOW(); //while(Busy_Wait()); Delay(10); }
void LCD_Data(unsigned int data) //This function is used to send data to LCD { unsigned int temp=0; EN_LOW(); DATA_PORT(); WRITE_DATA();
temp=data; //IO0PIN&=0xFF87FFFF; IO0PIN&=0x00010000; IO0PIN|=(temp & 0xF0) << 15;
EN_HI(); EN_LOW();
temp=data & 0x0F;
//IO0PIN&=0xFF87FFFF; IO0PIN&=0x00870000; IO0PIN|=(temp) << 19;
EN_HI(); EN_LOW(); Delay_Small(1); }
void LCD_Init()
{
LCD_Command(0x02);
LCD_Command(0x28);
LCD_Command(0x0C);
LCD_Command(0x06);
}
void LCD_String(unsigned char data) { while(data) { LCD_Data(*data); data++; } }
unsigned char str[32]=" "; char word[100], twoD[10][30]; int i = 0, j = 0, k = 0, len1 = 0, len2 = 0, l = 0; int main(void) { PINSEL0 = 0x00000000; // Enable GPIO on all pins PINSEL1 = 0x00000000; PINSEL2 = 0x00000000;
Delay(20);
IO0DIR = (1<<22) | (1<<21) | (1<<20) | (1<<19) | (1<<18) | (1<<17) | (1<<16); // Set P0.16, P0.17, P0.18, P0.19, P0.20, P0.21, P0.22 as Output
initClocks(); // Set CCLK=60Mhz and PCLK=60Mhz
initUART0();
while(1)
{
char c = U0Read(); // Read Data from Rx
if( c == ENTER ) // Check if user pressed Enter key
{
U0Write(c); // Send New Line ASCII code change line
break;
}
else
{
str[i]=c;
i++;
U0Write(c); // Write it to Tx to send it back
}
}
for (i = 0; str[i] != '\0'; i++)
{
if (str[i] == ' ')
{
twoD[k][j] = '\0';
k ++;
j = 0;
}
else
{
twoD[k][j] = str[i];
j ++;
}
}
twoD[k][j] = '\0';
j = 0;
for (i = 0; i < k; i++)
{
int present = 0;
for (l = 1; l < k + 1; l++)
{
if (twoD[l][j] == '\0' || l == i)
{
continue;
}
if (strcmp (twoD[i], twoD[l]) == 0) {
twoD[l][j] = '\0';
present = present + 1;
}
}
}
j = 0;
for (i = 0; i < k + 1; i++)
{
if (twoD[i][j] == '\0')
continue;
else
LCD_String(&twoD[i][0]);
}
LCD_Init();
LCD_Command(0x01);
Delay(20);
LCD_Command(0x80);
LCD_String(&str[0]);
LCD_Command(0xC0);
LCD_String(&str[16]);
return 0;}
void initUART0(void)
{
PINSEL0 = 0x5; / Select TxD for P0.0 and RxD for P0.1 /
U0LCR = 3 | (1<<7) ; / 8 bits, no Parity, 1 Stop bit | DLAB set to 1 /
U0DLL = 110;
U0DLM = 1;
U0FDR = (MULVAL<<4) | DIVADDVAL; / MULVAL=15(bits - 7:4) , DIVADDVAL=0(bits - 3:0) /
U0LCR &= 0x0F; // Set DLAB=0 to lock MULVAL and DIVADDVAL
//BaudRate is now ~9600 and we are ready for UART communication!
}
void U0Write(char data) { while ( !(U0LSR & THRE ) ); // wait till the THR is empty // now we can write to the Tx FIFO U0THR = data; }
char U0Read(void) { while( !(U0LSR & RDR ) ); // wait till any data arrives into Rx FIFO return U0RBR; }
void initClocks(void) { setupPLL0(); feedSeq(); //sequence for locking PLL to desired freq. connectPLL0(); feedSeq(); //sequence for connecting the PLL as system clock
//SysClock is now ticking @ 60Mhz!
VPBDIV = 0x01; // PCLK is same as CCLK i.e 60Mhz
//Using PLL settings as shown in : http://www.ocfreaks.com/lpc214x-pll-tutorial-for-cpu-and-peripheral-clock/
//PLL0 Now configured!}
//---------PLL Related Functions :---------------
void setupPLL0(void) { //Note : Assuming 12Mhz Xtal is connected to LPC2148.
PLL0CON = 0x01; // PPLE=1 & PPLC=0 so it will be enabled
// but not connected after FEED sequence
PLL0CFG = 0x24; // set the multipler to 5 (i.e actually 4)
// i.e 12x5 = 60 Mhz (M - 1 = 4)!!!
// Set P=2 since we want FCCO in range!!!
// So , Assign PSEL =01 in PLL0CFG as per the table.}
void feedSeq(void) { PLL0FEED = 0xAA; PLL0FEED = 0x55; }
void connectPLL0(void) { // check whether PLL has locked on to the desired freq by reading the lock bit // in the PPL0STAT register
while( !( PLL0STAT & PLOCK ));
// now enable(again) and connect
PLL0CON = 0x03;}