BASIC stamp manual v2.2

5: BASIC Stamp Command Reference – READ

BASIC Stamp Syntax and Reference Manual 2.2 • www.parallax.com • Page 371

' {$PBASIC 2.5}

result VAR Word

DATA Word 1125

READ 0, Word result

DEBUG DEC ? result

This code uses the EEPROM or DATA directive to write the low-byte and

high-byte of the number 1125 into locations 0 and 1 during download.

The BS1 code the uses two READ commands to read each of the bytes out

of EEPROM and reconstructs them into a single word-sized variable.

PBASIC 2.5 uses READ’s optional WORD modifier to read both bytes

from EEPROM and into a word-sized variable. Both programs then

display the value on the screen.

When using PBASIC 2.5, a single READ command can retrieve multiple

bytes and words from sequential EEPROM locations. For example:

' {$PBASIC 2.5}

temp VAR Byte

temp2 VAR Word

READ 25, temp, Word temp2 ' retrieve byte from location 25

' and word from locations 26 and 27

DEBUG DEC temp, CR ' display value of temp, carriage return

DEBUG DEC temp2 ' display value of temp2

Note that the EEPROM and DATA directives store data in the EEPROM

before the program runs, however, the WRITE command can be used to

store data while the program is running. Additionally, the EEPROM

locations can be read an unlimited number of times, but EEPROM

locations can be worn out by excessive writes. See the WRITE command

for more information.

When using the READ and WRITE commands, take care to ensure that

your program doesn’t overwrite itself. On the BS1, location 255 holds the

address of the last instruction in your program. Therefore, your program

can use any space below the address given in location 255. For example, if

location 255 holds the value 100, then your program can use locations 0–99

for data. You can read location 255 at run-time or simply view the

SPECIAL NOTES FOR EEPROM USAGE.

All