TI-57

In this article, we will explore the topic of TI-57 in depth, addressing its different aspects from a broad and detailed perspective. Over the next few lines, we will analyze in depth the importance and relevance of TI-57 today, as well as its possible impacts in different areas of daily life. To do this, we will examine different points of view, studies and opinions of experts on the subject, with the aim of offering the reader a complete and enriching vision about TI-57. Throughout this journey, we will immerse ourselves in both its history and its current events, trying to understand its evolution over time and its influence on society.

The programmable calculator TI-57 with LED display
The programmable calculator TI-57 LCD with liquid crystal display

The TI-57 was a programmable calculator made by Texas Instruments between 1977 and 1982. There were three machines by this name made by TI, the first was the TI-57 with LED display released in September 1977 along the more powerful TI-58 and TI-59. It had 50 program steps and eight memory registers. Two later versions named TI-57 LCD and TI-57 LCD-II have a LCD display, but were less powerful (ran much slower) and had much less memory: 48 bytes to be allocated between program 'steps' and storage registers.

The TI-57 lacked non-volatile memory, so any programs entered were lost when the calculator was switched off or the battery ran out.

The LED display version of the TI-57 had a rechargeable Nickel-Cadmium battery pack BP7 which contains 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 was self described as "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 were similar to a primitive macro assembler. Any keystroke could be stored, along with some simple program flow control commands and conditional tests. These included:

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 could be performed against a value on the display (the x register) and a dedicated test register, t. The result of the test would cause the next instruction to be conditionally skipped.

Programs could be edited by inserting, deleting, or overwriting a program step. A NOP (No OPeration) function was provided to allow a program step to be ignored. Due to the hard limit of 50 program steps, use of NOP was infrequent. The TI-57 used 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.

Step Code Key(s) Function Comment
00 30 2nd yx π Pi
01 75 + +
02 33 0 RCL 0 RCL 0 Recall register 0
03 85 =
04 35 yx yx
05 08 8 8
06 65 − −
07 49 2nd ) Int Integer function
08 85 =
09 32 0 STO 0 STO 0 Store result in register 0
10 55 x x
11 06 6 6 Upper bound of the random number
12 75 + +
13 01 1 1
14 85 =
15 49 2nd ) Int Integer function
16 81 R/S R/S Stop (Pause)
17 71 RST RST Reset (back to step 00)