	IP21 EAROM Description
	----------------------

The IP21 EAROM contains the R8000 boot-time serial bitstream data
and a number of constants which pertain to features which may change
during the evolution of the Everest system.  This file contains
a description of the EAROM contents.

In the following table, the byte numbers are in decimal.  Hexadecimal
values will be explicitly prefixed with '0x'.

Byte #		Description
------		-------------------------------------------------------------
0 - 0x1f	unused
0x20-0x23	Everest Bus Frequency in Hertz, specified as a 4-byte
		unsigned value.  Byte 40 is the LSB, and byte 43 is the MSB.
		INITIAL VALUE: 0x02d69be8 47.619048 MHz 

0x24		Piggy Back read enable feature, When this byte
                is set to 1, the PROM will turn on Piggyback Reads.

0x25-0x27	unused

0x28-0x2b	CPU frequency in Hz.
		INITIAL VALUE: 0x02faf080

0x2c-0x2f	Real Time Clock frequency in Hz
		INITIAL VALUE: 0x02d69be8

0x30-0x32	Number of times the EAROM has been written
		INITIAL VALUE: 1
		EAROM's can only be written a finite number of times before
		they begin to fail.  Every time the EAROM is written this
		value is updated, and when it goes above some critical
		value the PROM will display a warning. 

0x33-0x37	Configuration register timeout value

0x38-0x3f	unused

0x40-0x41	Checksum of the first 48 bytes of the EAROM

0x42-0x43	Checksom of the complement of the checksum

		
		INITIAL VALUE: 0x02faf080 (50,000,000)
