Why i do not drive the 93C46?

[jason540]

i try to write a program to drive 93C46(SPI EEROM), but it do not read data(may be do not write).
i want to know which part do not work.

Thank very much


Main Program

#include <p18f4620.h>
#include <delays.h>

#pragma config OSC = HS // use High Speed crystal (20MHz) - not using PLL right now
#pragma config PWRT = ON //Power up timer is ON
#pragma config WDT = OFF // Watchdog timer is OFF
#pragma config LVP = ON // Low Voltage Programming ON
#pragma config BOREN = OFF //Brown out reset is OFF
#pragma config DEBUG = ON //Debug is ON


#define CS LATDbits.LATD0 //Chip Select Latch = RD4
#define SCL LATCbits.LATC6 //Clock Latch = RC1
#define SDO LATCbits.LATC5 //Data Out Latch = RC5
#define SDI PORTCbits.RC4 //Data In Port = RC4
#define ORG LATCbits.LATC7


#define CST TRISDbits.TRISD0 //Chip Select TRIS=TRISD4
#define SCLT TRISCbits.TRISC6 //Clock TRIS=TRISC1
#define SDOT TRISCbits.TRISC5 //Data Out TRIS =TRISC5
#define SDIT TRISCbits.TRISC4 //Data In TRIS = TRISC2
#define ORGT TRISCbits.TRISC7

unsigned char val_1=0;

void main(void);
void initSPI(void);
unsigned char ReadSPI(unsigned char address);
void WriteSPI(unsigned char address, unsigned char data);
unsigned char SPI_RByte(void);
void SPI_WByte(unsigned char data);
void SPI_address(unsigned char address);



void main (void)
{
// Make bit 7 the Port D (LED) output bit.
TRISDbits.TRISD7 = 0;

//SPI init
initSPI();

while (1) {
TRISDbits.TRISD7 = 0;
TRISDbits.TRISD6 = 0;

val_1=0; // reset value
WriteSPI(0x05,0xAA); //Set up MMA7455L operation mode by writing to hex addr 16, hex value 05 (2g, 4 wires)
val_1 = ReadSPI(0x05); // read value back from register and if expected value turn ON the LED
if(val_1==0xAA){LATDbits.LATD7 = 1;Delay10KTCYx(300);} // turn LED ON
else if(val_1!=0xAA) {LATDbits.LATD7 = 0;} // turn LED OFF

};

}// End of the main program




void initSPI(void){
SCLT = 0; //Set the SCL (CLOCK) pin to output,
SDOT = 0; //Set the SDO (DATA OUT) pin to output,
SDIT = 1; //Set the SDI (DATA IN) pin to input,
CST = 0; //Set the CS (Chip Select) pin to output,
ORGT = 0; //Set the ORG pin to output

CS = 0; //Set Chip Select Low
SDO = 0; //Set Serial Data Out Low
SCL = 0; //Set Serial Clock Low
ORG = 0;
}


void SPI_WByte(unsigned char data)
{

char x;
for(x=0;x<8;x++){ //Loop 8 bits
SCL = 0; //Clock Low
SDO = 0; //Data Low

if((data & 0x80) != 0) //Clear entire byte except bit 7 and check if byte is greater than 0
SDO = 1; //Set the Data Out to HIGH
Delay10TCY(); //Delay 5uS
SCL = 1; //Clock High

Delay10TCY(); //Delay 5uS
data <<= 1; //Shift data bit out to the right
}
}

void SPI_address(unsigned char address)
{
char x;
for(x=0;x<10;x++){ //Loop 10 bits 3-bit instruction, 7-bit address
SCL = 0; //Clock Low
SDO = 0; //Data Low

if((address & 0x200) != 0) //Clear entire byte except bit 9 and check if byte is greater than 0
SDO = 1; //Set the Data Out to HIGH
Delay10TCY(); //Delay 5uS
SCL = 1; //Clock High

Delay10TCY(); //Delay 5uS
address <<= 1; //Shift data bit out to the right
}
}

unsigned char SPI_RByte(void){
char x,data;
for(x=0;x<8;x++){ //Loop 8 bits 8-bit data
SCL = 0; //Clock Low

Delay10TCY(); //5uS delay
data <<= 1; //Shift 1 bit to the left
data &= 0xFE; //Clear BIT 0 from byte without touching the rest
if(SDI) //if the Serial Data In is HIGH do below if not then leave it 0
data |= 1; //OR in a 1 into out byte
Delay10TCY(); //delay 5uS
SCL = 1; //Clock High

}
return data; //return our data
}

void WriteSPI(unsigned char address, unsigned char data){

SCL = 1; //Clock High
CS = 0; //Chip Select Low = SPI Enable
address = address | 0x280; //b101xxxxxxx is write instruction
SPI_address(0b1001100000);
SPI_address(address); //Write our address
SPI_WByte(data); //Write our data
CS = 1; //Chip Select High

}

unsigned char ReadSPI(unsigned char address){
unsigned char tmp;
SCL = 1; //Clock High
CS = 0; //Chip Select Low
address = address | 0x300; //110xxxxxxx is read instruction
SPI_address(address); //Write our address to read from
tmp = SPI_RByte(); //Get the byte from the device
CS = 1; //Chip Select High
return tmp; //Return tmp
}

 

[Electronworks]

Have you allowed 6ms for the EEPROM to program? I cannot see this in your code. Once you write data to the memory, you have to implement a wait delay (i normally use 10ms) for hte internal program cycle to complete.

If I had one 'stock' answer to solve most E2 read/write problems, this would be it

let me know

Thanks

 

[Pommie]

I don't see where you are sending an EWEN command.

Also, why aren't you using the hardware SPI unit?

Mike.

 

[jason540]

it is allow >6ms for the EEPROM to program?



i sending an EWEN instruction at void WriteSPI

void WriteSPI(unsigned char address, unsigned char data){

SCL = 1; //Clock High
CS = 0; //Chip Select Low = SPI Enable
address = address | 0x280; //0b101xxxxxxx is write instruction
SPI_address(0b1001100000); //0b10011xxxxx is a EWEN instruction
SPI_address(address); //Write our address
SPI_WByte(data); //Write our data
CS = 1; //Chip Select High
}

 

[blueroomelectronics]

Why aren't you using the hardware SPI unit?

 

[jason540]

because this is part of program, other part also use SPI to transmit data to Accelerometer and LCD display