PUT

Syntax: PUT Location, {WORD} Value{,{WORD} Value ...}

Function

Write one or more values to the Scratchpad RAM, starting at Location and building upward.

• Location is a variable/constant/expression (0 – 62 for BS2e and BS2sx, and 0 – 126 for BS2p, BS2pe, and BS2px) that specifies the Scratchpad RAM location to write to.
• Value is a variable/constant/expression to store in RAM.*

*Note: The optional arguments require PBASIC 2.5.

Quick Facts

Explanation

The PUT command writes a value into the specified Scratchpad RAM location(s). All values in the general-purpose locations can be written to from within any of the eight program slots.

Scratchpad RAM is useful for passing data to programs in other program slots and for additional workspace. It is different than regular RAM in that symbol names cannot be assigned directly to locations and each location is always configured as a byte only. The following code will write the value 100 to location 25, read it back out with GET and display it:

The following example illustrates this:

temp    VAR     Byte

Main:
  PUT 25, 100
  GET 25, temp
  DEBUG DEC temp
  END

When using $PBASIC 2.5 syntax, Word-sized variables can be written to the Scratchpad RAM with a single PUT statement, as well as multiple items to consecutive locations. The Word modifier writes the low-byte first, then the high-byte ("Little Endian").

' {$PBASIC 2.5}

value   VAR     Word
value2  VAR     Word
addr    VAR     Word                    ' EEPROM address
test    VAR     Byte                    ' test byte read back

Main:
  value = $11
  value2 = $2003
  PUT 0, value, Word value2             ' write value to SP location 0
                                        '  and value2 to SP locations 1 & 2

  value = $FF                           ' modify variables
  value2 = $FFFF

  GET 0, value, Word value2             ' retrieve from Scratchpad

  DEBUG HEX2 ? value                    ' display
  DEBUG HEX4 ? value2
  END

Most Scratchpad RAM locations are available for general use. The highest location (63 for BS2e/BS2sx and 127 for BS2p/BS2pe) is a special, read-only, location that always contains the number of the currently running program slot. On the BS2p/BS2pe, the upper nibble of location 127 also contains the current program slot that will be used for the READ and WRITE commands. Any values written to this location will be ignored.