f_11_16_spimemtst.c

PIC_Hi-Tech_C_Mike_Pearces_I2C_routines Microchi PIC_Hi-Tech C_I2C_for_EEPROM_24LC01B Code

#include "config.h"
#include "serial.c"
#include "serio.c"
#include "delay.h"

#define MEMCS 7
#define MEM_WREN  6
#define MEM_WRITE 2
#define MEM_READ 3
#define MEM_RDSR 5

//prototypes
void spi_memwren(void);
unsigned char spi_memrdsr(void);
void spi_memrw(char *buf, unsigned int addr, char write_flag);

// do write enable
void spi_memwren(void){
  bitclr(PORTB,MEMCS); // Assert CS
  SSPBUF = MEM_WREN;
  while(!SSPIF); // wait until transmited
  SSPIF = 0;     // reset
  bitset(PORTB,MEMCS); // Negate CS
}

// read status register
unsigned char spi_memrdsr(void){
  bitclr(PORTB,MEMCS); // Assert CS
  SSPBUF = MEM_RDSR;
  while(!SSPIF); // wait until transmited
  SSPIF = 0;     // reset
  SSPBUF = 0;    // dummy data for read
  while(!SSPIF); // wait until transmited
  SSPIF = 0;     // reset
  bitset(PORTB,MEMCS); // Negate CS
  return(SSPBUF); // return status
}




//write or read a block
void spi_memrw(char *buf, unsigned int addr, char write_flag){
  unsigned char addr_lo, addr_hi, status;
  char i;
  // ensure last write is finished
  do {
    status = spi_memrdsr();
  }while (status & 0x01);  //test bit 0 
  if (write_flag) spi_memwren(); // write enable
  addr_lo = addr & 0x00FF;
  addr_hi = (addr >> 8);
  bitclr(PORTB,MEMCS); // Assert CS
  if (write_flag)  SSPBUF = MEM_WRITE;
   else SSPBUF = MEM_READ;
  while(!SSPIF); // wait until transmited
  SSPIF = 0;     // reset
  SSPBUF = addr_hi;  // send high byte address
  while(!SSPIF); // wait until transmited
  SSPIF = 0;     // reset
  SSPBUF = addr_lo; // send low byte address
  while(!SSPIF); // wait until transmited
  SSPIF = 0;     // reset
  for (i=0;i<32;i++){ // send 32 bytes
    SSPBUF= *buf;  //for read, don't care about this data
    while(!SSPIF); // wait until transmited
    SSPIF = 0;     // reset
    if (!write_flag) *buf = SSPBUF;
    buf++;
  }
  bitset(PORTB,MEMCS); // Negate CS
}
  
char membuf[32];
int memaddr;
void main(void){
  unsigned char mode,i;

  // set RB7 for output
  TRISB = 0x7F; 
  bitset(PORTB,MEMCS);
  serial_init(95,1); // 19200 in HSPLL mode, crystal = 7.3728 MHz

  // configure SPI port for serial eeprom
  CKE = 1; // data transmitted rising edge of SCK
  CKP = 0; // clk idle is low
  SMP = 1; // sample data at end of period
  bitclr(TRISC,3);  //SCK, output
  bitclr(TRISC,5);  // SDO, output
  bitset(TRISC,4);  // SDI pin is input
  // SPI Master Mode FOSC/16
  SSPM3 = 0;  SSPM2 = 0; SSPM1 = 0;  SSPM0 = 1;
  SSPEN = 0;
  SSPEN = 1;
  SSPIF = 0;  // clear SPIF bit
  pcrlf();  printf("Mem Test Started");  pcrlf();

  memaddr = 0;
  printf ("Enter 'w' for write mode, anything else reads: ");
  mode = getche();
  pcrlf();
  while(1) {
    if (mode == 'w') {
      printf("Enter 32 chars.");pcrlf();
      for(i = 0;i< 32;i++) {
	membuf[i] = getche();
      }
      pcrlf();printf("Doing Write");pcrlf();
      spi_memrw(membuf,memaddr,1); // do write
      memaddr = memaddr +32;
    } else {
      spi_memrw(membuf,memaddr,0); // do read
      for(i = 0;i< 32;i++) putch(membuf[i]);
      pcrlf();
      printf("Any key continues read...");pcrlf();
      getch();
      memaddr = memaddr +32;
    }
  }
}