thumb|upright|TI-57 with [[LED display]]
thumb|upright|TI-57 with [[LCD technology for display]]
thumb|upright|TI-57-II (LCD)
The TI-57 is a discontinued product line of programmable calculators made by Texas Instruments between 1977 and 1982. There are three devices by this name made by TI. The first TI-57 devices with LED displays were released in September 1977 along the more powerful TI-58 and TI-59. The original devices have 50 program steps and eight memory registers. Two later versions named TI-57 LCD and TI-57 LCD-II have LCDs, but are less powerful (run much slower) and have much less memory: 48 bytes to be allocated between program 'steps' and storage registers.
The TI-57 lacks non-volatile memory, so any programs entered are lost when the calculator is switched off or the battery runs out.
The LED display version of the TI-57 was sold with a rechargeable nickel–cadmium battery pack BP7 containing two AA size batteries and electronics to raise the voltage to the 9V required by the calculator. A popular modification is to power it from a 9V battery and use the battery cover of a LED TI-30 or a part of the dismantled battery pack. This modification provides a better battery life than the original battery pack.
Included, with at least the original version, was a book entitled Making Tracks Into Programming. It is subtitled "A step-by-step learning guide to the power, ease and fun of using your TI Programmable 57".
Radio Shack also marketed this calculator, rebranded as the EC-4000.
Programming
The programming capabilities of the TI-57 are similar to a primitive macro assembler.
Any keystroke can be stored, along with some simple program flow control commands and conditional tests. These include:
GTO (GoTO): Causes program pointer to jump immediately to a Label (0-9) or to a specific program step (00 to 49).
SBR (SuBRoutine): Causes a program to jump to a Label, and on encountering an Inv SBR command, continue executing at the instruction immediately following the original SBR.
DSZ (Decrement and Skip on Zero): Decrements storage register zero, and skips the next instruction if the result is zero. There was also an inverse form, Decrement and Skip if Not Zero.
Tests for equality/inequality can be performed against a value on the display (the x register) and a dedicated test register, t. The result of the test causes the next instruction to be conditionally skipped.
Programs can be edited by inserting, deleting, or overwriting a program step.
A NOP (No OPeration) function is provided to allow a program step to be ignored.
Due to the hard limit of 50 program steps, use of NOP is infrequent.
The TI-57 uses the "one step, one instruction" principle, regardless of whether one instruction required one or up to four keypresses.
Sample program
The following program generates pseudo-random numbers within the range of 1 to 6.
{| class="wikitable"
! Step
! Code
! Key(s)
! Function
! Comment
|-
|00
|30
|align="center" |
|align="center" | π
|Pi
|-
|01
|75
|align="center" |
|align="center" | +
|
|-
|02
|33 0
|align="center" |
|align="center" | RCL 0
|Recall register 0
|-
|03
|85
|align="center" |
|align="center" | =
|
|-
|04
|35
|align="center" |
|align="center" | y<sup>x</sup>
|
|-
|05
|08
|align="center" |
|align="center" | 8
|
|-
|06
|65
|align="center" |
|align="center" | −
|
|-
|07
|49
|align="center" |
|align="center" | Int
|Integer function
|-
|08
|85
|align="center" |
|align="center" | =
|
|-
|09
|32 0
|align="center" |
|align="center" | STO 0
|Store result in register 0
|-
|10
|55
|align="center" |
|align="center" | x
|
|-
|11
|06
|align="center" |
|align="center" | 6
|Upper bound of the random number
|-
|12
|75
|align="center" |
|align="center" | +
|
|-
|13
|01
|align="center" |
|align="center" | 1
|
|-
|14
|85
|align="center" |
|align="center" | =
|
|-
|15
|49
|align="center" |
|align="center" | Int
|Integer function
|-
|16
|81
|align="center" |
|align="center" | R/S
|Stop (Pause)
|-
|17
|71
|align="center" |
|align="center" | RST
|Reset (back to step 00)
|}
External links
- TI-57 on MyCalcDB (database about 1970s and 1980s pocket calculators)
- TI-57 on The Datamath Calculator Museum.
- TI-57 Program Emulator including a few dozen examples of games and other programs.
- TI-57 Programmable Calculator including an emulator with original ROM and diagnostics.