HP-15C
HP-15C Quick Reference
A. Thimet
Memory & Display
Memory
Approx. 462 bytes of memory corresponding to 66 registers, 7 bytes each,
4-level stack, Last-X, index register I.
Nonvolatile memory, mostly merged program commands (1 byte per
instruction)
Pr Error
Displayed when the contents of the nonvolatile (continuous memory) has
been lost
Number
separator
Turn off, press & hold ON, press ".", release ON, release "."
This toggles between using a dot or comma for the decimal separator.
Global
reset
Turn off, press & hold ON, press "-", release ON, release "-"
This clears all permanent memory!
MEM
Displays memory assignment in the form "RR UU pp – n" with:
RR: Number of highest storage register. At least 1 which means that R0, R1
and the index register I are always present. Register 0-19 correspond to
0-9 & .0-.9 and can be accessed directly by STO/RCL. Higher registers
can be reached thru indirect addressing only.
UU: Number of uncommitted registers. Use DIM to commit them to storage
registers. Uncommitted registers are automatically converted to
program space when needed.
pp: Number of registers containing program instructions. One register
consists of 7 bytes and can hold 7 program steps (except for a few
instructions that occupy two bytes).
n:
Number of bytes left before next uncommitted register is converted to
program space.
In total there are 66 registers corresponding to 462 bytes.
The initial setup is "19 46 0-0": 20 storage registers (0-19), 46 uncommitted
registers, corresponding to approx. 322 program steps.
DIM (i)
Use this command to select the number of registers committed to storage.
The argument must be passed in X. It specifies the highest storage register
number.
Registers containing program instructions cannot be converted to storage
registers!
X must be at least 1 so there will always be R0 and R1 available.
The maximum is 65
FIX 0-9
Select fix-point format
SCI 0-9
Select scientific format with exponent
ENG 0-9
Select engineering format with exponent always being a multiple of 3
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