Parallax BASIC Stamp 1, Programming Manual

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5: BASIC Stamp Command Reference - EEPROM
BASIC Stamp Programming Manual 2.0c
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EEPROM (72, 69, 76, 76, 79)
EEPROM ("H", "E", "L", "L", "O")
EEPROM ("HELLO")
All three lines of code, above, will result in the numbers 72, 69, 76, 76, and
79 being stored into EEPROM upon downloading. These numbers are
simply the ASCII character codes for "H", "E", "L", "L", and "O",
respectively. See the Demo Program, below, for an example of storing and
reading multiple text strings.
The EEPROM is organized as a sequential set of byte-sized memory
locations. The EEPROM directive only stores bytes into EEPROM. If you
try to store a word-size value, for example: EEPROM (1125), only the
lower byte of the value will be stored (in this case, 101). This does not
mean that you can't store word-sized values, however. A word consists of
two bytes, called a low-byte and a high-byte. If you wanted to store the
value 1125 using the EEPROM directive you'll have to calculate the low-
byte and the high-byte and insert them in the list in the proper order, as in:
EEPROM (101, 4)
The directive above will store the two bytes into two sequential EEPROM
locations (the low-byte first, followed by the high-byte). We calculated
this in the following manner: 1) high-byte is INT(value / 256) and 2) low-
byte is value – (high-byte * 256).
To retrieve a word-size value, you'll need to use two READ commands
and a word-size variable. For example,
SYMBOL Result = W0 'The full word-sized variable
SYMBOL Result_Low = B0 'B0 happens to be the low-byte of W0
SYMBOL Result_High = B1 'B1 happens to be the high-byte of W0
EEPROM (101, 4)
READ 0, Result_Low
READ 1, Result_High
DEBUG #Result
This code would write the low-byte and high-byte of the number 1125 into
locations 0 and 1 during download. When the program runs, the two
READ commands will read the low-byte and high-byte out of EEPROM
(reconstructing it in a word-size variable) and then display the value on
the screen. See the READ and WRITE commands for more information.
W
RITING WORD VALUES VS
.
BYTE
VALUES
.