SPI_EEPROM INTERFACE WITH LPC2114

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pavan_85

Joined: 03 Jul 2008
Posts: 27
Helped: 1
Location: hyderabad

29 Oct 2009 17:35 SPI_EEPROM INTERFACE WITH LPC2114

hi all,
does any one of u have schematic for interface of spi eeprom (like 25c160 or any other IC) with lpc 2114......

if s pleaz post it......

thanks in advance...
pavan

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29 Oct 2009 17:35 Ads

bobcat1

Joined: 10 Jul 2002
Posts: 1118
Helped: 48

31 Oct 2009 13:22 Re: SPI_EEPROM INTERFACE WITH LPC2114

Hi

To interface SPI is a bit easy all you need is to connect 4 wire

CLK (LPC21xx) -> CLK(25xx)
CS (LPC21xx)(can be any I/O ->CS(25xx)
MOSI (LPC21xx) -> MOSI(25xx)
MISO (LPC21xx) <- MISO(25xx)

You also need to connect vcc & Gnd to the 25xx chip and add some 100nF cap near the 25xx vcc pin

For software you will need to use the SPI protocol Driver (can be found in NXP site or search SPI & LPC in google) And a protocol software layer for the 25xxx (search 25xx and code in google )

All the best

Bobi

The microcontroller specialist

pavan_85

Joined: 03 Jul 2008
Posts: 27
Helped: 1
Location: hyderabad

05 Nov 2009 17:03 Re: SPI_EEPROM INTERFACE WITH LPC2114

hi all,
I was trying to simulate spi interface with protues;
memory - AT25F512A
uc - LPC 2141

My problem is that S0SPDR register is not getting updated.......
here is my code..please go through it and comment where i went wrong.....

waiting for your replies......
pavan.

Code:

#include <lpc21xx.h>

void pll_init(void);
extern unsigned char rd[5];
int main()
{

//INITIALIZE THE PLL AND SET CCLK = PCLK = 12Mhz
pll_init();

//SPI ROUTINES
spi_init();
spi_write("lucky");
}

void pll_init(void)
{
PLLCFG = 0X00000060;
PLLCON = 0X00000001;
PLLFEED = 0X000000AA;
PLLFEED = 0X00000055;

while(!(PLLSTAT&0X00000400));

PLLCON = 0X00000003;

PLLFEED = 0X000000AA;
PLLFEED = 0X00000055;

VPBDIV = 0X09;
}
------------------------------------------------------------------
SPI CODE
------------------------------------------------------------------
#include <lpc21xx.h>

#include "spi.h"

#define READ 0x03       // WRITE LATCH ENABLE
#define WRITE 0x02       // WRITE DATA (PROGRAM)
#define WRDI 0x04       // RESET WRITE ENABLE
#define WREN 0x06       // READ DATA FROM MEMORY
#define RDSR 0x05       // READ STATUS REGISTER
#define WRSR 0x01       // WRITE STATUS REGISTER
#define SPIF    1 << 7

unsigned char rd[5];

void spi_init(void)
{
PINSEL0 = 0x00005500; // SELECTING SPI MODE
S0SPCCR = 0x78;       // 100KHZ
S0SPCR = 0x20;       // MASTER MODE WITH 8-BITS PER TRANSFER
//IODIR0 = 0x00000080; // DECLARING SSEL0 AS AN OUTPUT
}

unsigned char spi_tx_rx(unsigned char val)
{

S0SPDR = val;
while((S0SPSR & SPIF)==0);
return S0SPDR;

}

void spi_write(unsigned char *val)
{
spi_tx_rx(WREN);
   spi_tx_rx(WRITE);
spi_tx_rx(0X00); //ADDRESS: HIGHER BYTE
spi_tx_rx(0X00); //ADDRESS: LOWER BYTE
spi_tx_rx(0X00);
while(*val)
{
   spi_tx_rx(*val++);
}

wait();
}

void spi_read()
{
int i;

spi_tx_rx(READ);
spi_tx_rx(0X00); //ADDRESS: HIGHER BYTE
spi_tx_rx(0X00); //ADDRESS: LOWER BYTE
for(i=0;i<5;i++)
{
   rd[i] = spi_tx_rx(0x00);
   wait();
}

}
/*
void write(unsigned char *dataa)
{
while(*dataa)
   spi_write(*dataa++);
}

void read(void)
{
int i;
spi_read();
for(i=0;i<5;i++)
{
   rd[i] = spi_read();
   wait();
}
}
*/
void wait()
{
int j;
for(j=0;j<50000;j++);
}