为什么18f46k80 EEPROM写入时间是从65ms到170ms不等?

我正在写数据串行传输到EEPROM。我已实现以下代码来写入EEPROM：查看带作用域的警告，写入时间从65ms到170ms不等。说明书上说4ms。我已连接了ICD3，并且正在使用XC8编译器。19字节时，需要2.7s来写入EEPROM，所以确实非常长。有人经历过类似的事情吗？谁能想到什么会引起这个？我跑的是64兆赫。



      以下为原文

    I am writing data transmitted serially to EEPROM.  I have implemented the following code to write to EEPROM:


char eep_wr_byte( unsigned char hi, unsigned char lo, unsigned char b ) {
  char read_back=0xff;
  gpio_led_warn( 1 );
  rupt_gie_set( FALSE );

  EEADRH = hi;
  EEADR = lo;
  EEDATA = b;
  EECON1bits.WREN = TRUE;
  EECON2 = 0x55;
  EECON2 = 0xAA;
  EECON1bits.WR = TRUE;

  while( EECON1bits.WR );

  EECON1bits.WREN = FALSE;
  rupt_gie_set( TRUE );
  gpio_led_warn( 0 );

  read_back = eep_rd_byte( hi, lo );

  return (b != read_back || EECON1bits.WRERR );


Looking at the warning led with a scope, the write time varies from 65ms to 170ms.  The spec says 4ms.  I have the ICD3 connected and I am using the XC8 compiler.

At 19 bytes, it takes 2.7s to write to EEPROM, so really, really long.  Anyone else experience this or something similar?  Anyone have any thoughts what could be causing this?  I'm running at 64MHz.