I am using PIC32MX350F128L Microcontroller to read from and write to EEPROM(SST26VF032B) using SPI communication. SPI communication in this program is working, I have checked it by sending JEDEC code which is provided in the SST26VF032B datasheet. So when i send 0x9F i am getting 3 bytes of data as mentioned in the datasheet. When i run now i am sending a string of data to a specific address of eeprom and getting 0xff in return. I am erasing the eeprom before writing into it. So i think i am getting 0xff after erasing the eeprom. The writing, reading operations are not working. If i send a string of value or a BYTE i am getting 0xff in return. So can u guys please suggest me where i am going wrong. I am using UART for debugging purpose to read values recieved through spi communication. The complete code is below, i am using MPLAB X.
Best Regards
Sandesh
#include <xc.h>
#include <stdio.h>
#include <plib.h>
#include <p32xxxx.h>
/* Configuration Bits */
#pragma config FSRSSEL = PRIORITY_7 // Shadow Register Set Priority Select (SRS Priority 7)
#pragma config PMDL1WAY = ON // Peripheral Module Disable Configuration (Allow only one reconfiguration)
#pragma config IOL1WAY = ON // Peripheral Pin Select Configuration (Allow only one reconfiguration)
// DEVCFG2
#pragma config FPLLIDIV = DIV_2 // PLL Input Divider (2x Divider)
#pragma config FPLLMUL = MUL_20 // PLL Multiplier (20x Multiplier)
#pragma config FPLLODIV = DIV_1 // System PLL Output Clock Divider (PLL Divide by 1)
// DEVCFG1
#pragma config FNOSC = PRIPLL // Oscillator Selection Bits (Primary Osc (XT,HS,EC))
#pragma config FSOSCEN = ON // Secondary Oscillator Enable (Enabled)
#pragma config IESO = ON // Internal/External Switch Over (Enabled)
#pragma config POSCMOD = HS // Primary Oscillator Configuration (XT osc mode)
#pragma config OSCIOFNC = ON // CLKO Output Signal Active on the OSCO Pin (Enabled)
#pragma config FPBDIV = DIV_1 // Peripheral Clock Divisor (Pb_Clk is Sys_Clk/8)
#pragma config FCKSM = CSECME // Clock Switching and Monitor Selection (Clock Switch Disable, FSCM Disabled)
#pragma config WDTPS = PS1048576 // Watchdog Timer Postscaler (1:1048576)
#pragma config WINDIS = OFF // Watchdog Timer Window Enable (Watchdog Timer is in Non-Window Mode)
#pragma config FWDTEN = OFF // Watchdog Timer Enable (WDT Disabled (SWDTEN Bit Controls))
#pragma config FWDTWINSZ = WINSZ_25 // Watchdog Timer Window Size (Window Size is 25%)
// DEVCFG0
#pragma config DEBUG = OFF // Background Debugger Enable (Debugger is Disabled)
#pragma config JTAGEN = OFF // JTAG Enable (JTAG Disabled)
#pragma config ICESEL = ICS_PGx2 // ICE/ICD Comm Channel Select (Communicate on PGEC2/PGED2)
#pragma config PWP = OFF // Program Flash Write Protect (Disable)
#pragma config BWP = OFF // Boot Flash Write Protect bit (Protection Disabled)
#pragma config CP = OFF // Code Protect (Protection Disabled)
/* MACRO DEFINITIONS */
/* Defining the Slave Select Pin */
#define SS LATDbits.LATD9
/* Defining the System Clock Frequency */
#define SYSCLK 40000000
/* Macro to get array size in bytes
* note that array size can't be found after passing pointer to a function */
#define LEN(x) (sizeof(x) / sizeof(x[0]))
/* SST26VF032B EEPROM instructions */
/* Write Enable */
#define WREN 0x06
/* Write Disable */
#define WRDI 0x04
/* Initialize Start of Write Sequence */
#define WRITE 0x02
/* Initialize Start of Read Sequence */
#define READ 0x03
/* Erase all sectors of Memory */
#define CE 0xc7
/* Read STATUS Register */
#define RDSR 0x05
/* Function Prototypes */
/* UART bit configuration */
void Bitconfig_uart(void);
/* SPI Initialization */
void SPI1_Init(void);
/* UART Initialization */
void Init_uart(void);
/* Send a Character Byte through UART */
void UART5PutChar(char Ch);
/* Function to Read and Write SPI1 buffer */
int SPI1_transfer( int b);
/* Function to check the Status of SPI */
void waitBusy();
/* Function to erase the contents in EEPROM */
void eraseEEPROM();
/* Function to Read data from EEPROM */
void readEEPROM( int address, char* loadArray, int loadArray_size);
/* Function to Write to EEPROM */
void writeEEPROM( int address, char* storeArray, int storeArray_size);
/* Global Variables Declaration */
/* Declare variables to check the functionality of EEPROM */
int i,j = 0;
char st = 0x9F;
char rec;
int x,y,z;
/*******************************************************************************
* Function Name: main()
********************************************************************************
* Summary:
* Initializes SPI
* Erase EEPROM
* Writes to EEPROM
* Read from EEPROM
*
* Parameters:
* None.
*
* Return:
* None.
*
*******************************************************************************/
int main()
{
int i;
/* Clock Setting */
SYSTEMConfigPerformance(SYSCLK);
/* UART bit configuration */
Bitconfig_uart();
/* Set the Controller OScillator Register bits */
//OSCCON = 0x00002200;
/* Initialize a String to Write to EEPROM and an array to Read back contents */
char writeData[] = "123456789ABCDEF";
/* Array to read 35 bytes of data */
char readData[15];
/* SPI Initialization */
SPI1_Init();
/* UART Initialization */
Init_uart();
/* Erase contents of EEPROM */
eraseEEPROM();
/* Write contents of writeData array to address 180 */
writeEEPROM( 0x1000, writeData, LEN(writeData));
/*
JEDEC Code (working) getting output as per datasheet (0x9F = 159)
SS=0;
SPI1_transfer(159);
x=SPI1_transfer(0);
UART5PutChar(x);
y=SPI1_transfer(0);
UART5PutChar(y);
z=SPI1_transfer(0);
UART5PutChar(z);
*/
while(1)
{
/* Read contents of EEPROM into readData array
* start at address 180 and read up to 180+length(readData) */
readEEPROM( 0x1000, readData, LEN(readData) );
}
} /* END main() */
/*******************************************************************************
* Function Name: SPI1_Init()
********************************************************************************
* Summary:
* SPI1 Initialization
*
* Parameters:
* None.
*
* Return:
* None.
*
*******************************************************************************/
void SPI1_Init(void)
{
/* Configure Peripheral Pin Select (PPS) for the SPI1 module
* Note: SS will be toggled manually in code
* SCK is hardwired to pin 55 */
/* Output Pin Selection */
RPE5R = 8;
SDI1R = 3;
/* RB4 (Slave Select 1) : output */
TRISDbits.TRISD9 = 0;
/* SPI configuration */
/* SPI1CON Register Configuration
* MSTEN: Master Mode Enable bit = 1 (Master)
* CKP (clock polarity control) = 0
* CKE (clock edge control) = 1
* ON: SPI Peripheral On bit
* 8-bit, Master Mode */
SPI1CON = 0x8120;
/* SPI1BRG Register Configuration */
SPI1BRG = 0x4D;
//REFOCONbits.ON = 1;
// REFOCONbits.DIVSWEN = 1;
}
/*******************************************************************************
* Function Name: SPI1_transfer()
********************************************************************************
* Summary:
* Write to and Read from SPI1 buffer
*
* Parameters:
* char b - Writes a Character to Buffer
*
* Return:
* Char - Returns the Character Read from EEPROM
*
*******************************************************************************/
int SPI1_transfer( int b)
{
/* write to buffer for TX */
SPI1BUF = b;
/* wait transfer complete */
while(!SPI1STATbits.SPIRBF);
/* read the received value */
return SPI1BUF;
} /* END SPI1_transfer() */
/*******************************************************************************
* Function Name: waitBusy()
********************************************************************************
* Summary:
* Checks if EEPROM is ready to be modified and waits if not ready
*
* Parameters:
* None.
*
* Return:
* None.
*
*******************************************************************************/
void waitBusy()
{
char status = 0;
do{
/* Select EEPROM */
SS = 0;
/* Read EEPROM status register */
SPI1_transfer(RDSR);
/* send dummy byte to receive incoming data */
status = SPI1_transfer(0);
/* Release EEPROM */
SS = 1;
}
/* write-in-progress while status<0> set to '1' */
while( status & 0x01);
} /* END waitBusy() */
/*******************************************************************************
* Function Name: readEEPROM()
********************************************************************************
* Summary:
* Reads data from EEPROM
*
* Parameters:
* Inputs: address - EEPROM address
* loadArray - array to load EEPROM data to
* loadArray_size - number of bytes of EEPROM data to load into array
*
* Return:
* None.
*
*******************************************************************************/
void readEEPROM( int address, char* loadArray, int loadArray_size)
{
int i;
/* Wait until EEPROM is not busy */
waitBusy();
/* Select EEPROM */
SS = 0;
/* Initiate Read */
SPI1_transfer( READ);
/* Address must be 16-bits but we're transferring it in two 8-bit sessions */
SPI1_transfer( address >> 16);
SPI1_transfer( address >> 8);
SPI1_transfer( address);
/* Request and store loadArray_size number of bytes into loadArray */
for( i=0 ; i<loadArray_size ; i++)
{
/* send dummy byte to read 1 byte */
loadArray[i] = SPI1_transfer( 0x00);
}
/* Release EEPROM */
SS = 1;
/* UART Test */
for(i=0;i<35;i++)
{
UART5PutChar(loadArray[i]);
for(j=0;j<20000;j++)
{}
}
} /* END readEEPROM() */
/*******************************************************************************
* Function Name: writeEEPROM()
********************************************************************************
* Summary:
* Write data to EEPROM
*
* Parameters:
* Inputs: address - EEPROM address
* storeArray - array of which contents are stored in EEPROM
* storeArray_size - number of bytes in array to store into EEPROM
*
* Return:
* None.
*
*******************************************************************************/
void writeEEPROM( int address, char* storeArray, int storeArray_size)
{
int i;
/* Wait until EEPROM is not busy */
waitBusy();
/* Select EEPROM */
SS = 0;
/* Send WRITE_ENABLE command */
SPI1_transfer( WREN);
/* Release EEPROM */
SS = 1;
/* Select EEPROM again after WREN cmd */
SS = 0;
/* Initiate Write */
SPI1_transfer( WRITE);
SPI1_transfer( address >> 16 );
SPI1_transfer( address >> 8 );
SPI1_transfer( address );
/* write 1 byte at a time from array */
/* MSB at lowest address (0 - first letter in string) */
for( i=0 ; i<storeArray_size; i++)
{
/* Initiate Write */
SPI1_transfer( WRITE);
SPI1_transfer( (address+i) >> 16 );
SPI1_transfer( (address+i) >> 8 );
SPI1_transfer( address+i );
SPI1_transfer( storeArray[i]);
}
/* Release EEPROM */
SS = 1;
} /* END writeEEPROM() */
/*******************************************************************************
* Function Name: eraseEEPROM()
********************************************************************************
* Summary:
* Erase entire contents of EEPROM
*
* Parameters:
* None
*
* Return:
* None.
*
*******************************************************************************/
void eraseEEPROM()
{
/* Wait until EEPROM is not busy */
waitBusy();
/* Select EEPROM */
SS = 0;
/* Send WRITE_ENABLE command */
SPI1_transfer( WREN);
/* Release EEPROM */
SS = 1;
/* Select EEPROM again after WREN cmd */
SS = 0;
/* send CHIP_ERASE command */
SPI1_transfer( CE);
/* Release EEPROM */
SS = 1;
} /* END eraseEEPROM() */
/*******************************************************************************
* Function Name: Init_uart()
********************************************g************************************
* Summary:
* Initialize UART4
*
* Parameters:
* None
*
* Return:
* None.
*
*******************************************************************************/
void Init_uart()
{
/* Enable UART */
U5MODEbits.ON = 1 ;
/* set baud rate(9600) */
U5BRG = 521;
/* Set U4STA Register for Enabling tx and rx */
U5STA=0x9400;
}
/*******************************************************************************
* Function Name: UART4PutChar(unsigned char Ch)
********************************************************************************
* Summary:
* Send data from controller to putty GUI
*
* Parameters:
* input
* unsigned char Ch - To Send a byte of data over UART
*
* Return:
* None.
*
*******************************************************************************/
void UART5PutChar(char Ch)
{
while(U5STAbits.UTXBF == 1);
U5TXREG=Ch;
}
/*******************************************************************************
* Function Name: Bitconfig_uart()
********************************************************************************
* Summary:
* UART Pin Configuration
*
* Parameters:
* None
*
* Return:
* None.
*
*******************************************************************************/
void Bitconfig_uart(void)
{
/* UART4 Initialization */
// OSCCON=0x00002200;
/* Set pins as digital */
ANSELBbits.ANSB2 = 0;
ANSELBbits.ANSB0 = 0;
/* Set UART Tx pin as Output */
TRISBbits.TRISB0 = 0; //in controler tx
TRISBbits.TRISB2 = 1; // in controller RX
/* Peripheral Pin select for UART4 */
U5RXR=0x07;
RPB0R=0x04;
}
