MEMORY MAP FOR THE CRICKET SYSTEM

There are three types of memory in the cricket:

* the PIC's ROM (2048 words of 14 bits)

* the PIC's RAM (96 bytes)

* the external EEPROM (4096 bytes)

The PIC's ROM stores the Cricket Logo interpreter/operating system.
Handy Crickets use "OTP" (one-time programmable) PIC chips, so this
can only be changed when Crickets are first manufactured.
 
The PIC's RAM stores internal interpreter state, the user code
execution stack, and user globals.

The user Logo program, user data arrays, and user recorded data, goes
in the external EEPROM.


LAYOUT OF THE EXTERNAL EEPROM

0x000-0xfef (user data)      4080 bytes
0xff0/0xff1 (button #1 ptr)     2 bytes
0xff2/0xff3 (button #2 ptr)     2 bytes
0xff4-0xffe (cricket name)     11 bytes
0xfff       (autostart flag)    1 byte

user data has (in order)
* user arrays
* user program
* user record data (beginning at 0x500)