lpc2148

Development Boards MicroMod
1

Hello All,

i’m struggling to receive data from gps receiver module to terminal window using lpc2148 in keiluvision 4 .i’m getting some junk data on terminal window.my baud rate is correct,i tried so many ways but i couldn’t catch the error.Any one give some idea to solve this issue.

2

naz:
Hello All,

i’m struggling to receive data from gps receiver module to terminal window using lpc2148 in keiluvision 4 .i’m getting some junk data on terminal window.my baud rate is correct,i tried so many ways but i couldn’t catch the error.Any one give some idea to solve this issue.

well, you’ve given us no specific symptoms. I have received 4800baud NMEA sentences on an LPC2106. Do you have the serial data voltage levels and data polarity correct?

3

Your baud rate might be correct, but are your clocks set up correctly?

Can you use a different device to input correct data to the processor (like a computer)?

Can you post any code from your MCU setup routines?

4

Transmit ‘U’ continuously and use a scope to check the baud rate.

Leon

5

this is the code which i have tried.could u please tell where i’m doing the mistake

#include<LPC214x.h>

#include<stdio.h>



void led(int);

void wait(void);



void serial(void);

char sendchar(char ch);

char recechar(void);



void __irq FIQ_Handler(void);

int main()

{

int ch;

IODIR1=0x00FF0000;

serial();

led(16); 

EXTMODE |=0x02;//level sensitivity for EINT1 

EXTPOLAR |=0x02;//polartiy for EINT1

PINSEL0|=0x20000000; //GPIO0.14,EINT1

EXTINT =0x00000002;	 //clear EINT flag register	

VICIntEnable=0x00008000;

VICIntEnable=0x00008000; //enable interrupt 15

while(1)

{

recechar();

led(17);

ch=U1RBR;

sendchar(ch);

led(18); 

}

}

void serial() 

{

PINSEL0=0xFFF0FFFF;	//clear uart1

PINSEL0|=0x00050000;//TX,RX of uart1 

U1LCR =0x83;//8bit,no parity,1stop bit,enable DLAB

U1DLM =0x01;

U1DLL=0x87;

U1LCR&=0x7F;   //disable DLAB

U1IER = 0x07;	//enable interrrupt

}

char sendchar(char ch)

{

if(ch=='\n')

 { 

  	while(!(U1LSR&0x20));

	U1THR=0x0D;

 }

while(!(U1LSR&0x20));

return(U1THR); 

}

char recechar()

{



while(!(U1LSR&0x01));

if(U1RBR=='

[/quote])

led(23);

return(U1RBR);

}

void led(int n)

{

IOSET1|=1<<n;

wait();

IOCLR1|=1<<n;

wait();

}

void wait()

{

int i;

for(i=0;i<8000000;i++);

}

void __irq FIQ_Handler()

{

EXTINT&=0x00000002; //disable interrupt.

}


[/quote]
6

Here is some UART code I use:

//------------------------ UART1 ISR ------------------------//
static void uart1ISR(void)
{
  /* Read IIR to clear interrupt and find out the cause */
  unsigned iir = U1IIR;

  /* Handle UART1 interrupt */
  switch ((iir >> 1) & 0x7)
    {
      case 1:
        /* THRE interrupt */
        break;
      case 2:
        /* RDA interrupt */
        do
          {
          uint16_t temp;

          // calc next insert index & store character
          temp = (uart1_rx_insert_idx + 1) % UART1_RX_BUFFER_SIZE;
          uart1_rx_buffer[uart1_rx_insert_idx] = U1RBR;

          // check for more room in queue
          if (temp != uart1_rx_extract_idx)
            uart1_rx_insert_idx = temp; // update insert index
          }
        while (U1LSR & 0x01);

        break;
      case 3:
        /* RLS interrupt */
        break;
      case 6:
        /* CTI interrupt */
        break;
   }
}

/* Description:  
 *    This function gets a character from the UART1 receive queue
 *
 * Calling Sequence: 
 *    void
 *
 * Returns:
 *    character on success, -1 if no character is available
 *
 *****************************************************************************/
int uart1Getch(void)
{
  uint8_t ch;

  if (uart1_rx_insert_idx == uart1_rx_extract_idx) // check if character is available
    return -1;

  ch = uart1_rx_buffer[uart1_rx_extract_idx++]; // get character, bump pointer
  uart1_rx_extract_idx %= UART1_RX_BUFFER_SIZE; // limit the pointer
  return ch;
}


 //put this in the init. function

  // initialise PLL

  PLL0CFG=0x24;      // Cclk = 60Mhz
  PLL0CON=0x01;
  PLL0FEED=0xAA;
  PLL0FEED=0x55;
  while(!(PLL0STAT & 0x0400))
	;
  PLL0CON=0x3;
  PLL0FEED=0xAA;
  PLL0FEED=0x55;

  // initialise MAM and VPB

  MAMTIM=0x3;       // 3 cycles to read from FLASH
  MAMCR=0x2;        // MAM functions fully enabled
  APBDIV=0x02;      // Pclk = 30MHz

  // initialise pclk (30 MHz)
  unsigned long pclk = liblpc2000_get_pclk(liblpc2000_get_cclk(OSCILLATOR_CLOCK_FREQUENCY));

 // initialise UART1 (RxD1 P0.9, TxD1 P0.8

  U1LCR = 0x83; // 8 bit, 1 stop bit, no parity, enable DLAB
  U1DLL = 0xC3; // set for 9600 baud
  U1DLM = 0x00;
  U1LCR &= ~0x80; // disable DLAB
  U1FCR = 1;      // enable FIFO
  PINSEL0 = PINSEL0 & ~(0xFFFF << 16) | (0x5555 << 16);

 // initialise Rx circular buffer
  uart1_rx_extract_idx = uart1_rx_insert_idx = 0;

You probably don’t need the circular buffer, so you can remove the relevant code.

Leon