Texas Instruments TI-57 LCD
Designed to be the successor to the TI-55, the TI-55-II has much more functions: signum, integer, fraction, and absolute values, combinatorial calculations, and easier programmability.
The only setback was the memory: when allocating (partitioning) the memory to storage registers and program area, the maximal available 56 steps cost almost all storage registers, only one can be used. Overall, at a given program length, the new model has fewer memory registers by two than its predecessor.
Unfortunately, the TI-57 was not so successful: because the TI-57 LCD was created by modification of the TI-55-II, much of the program stored in the ROM was sacrificed to implement the more advanced programming model: the statistical calculations were completely gone, and only the most necessary scientific functions remained. Due to the limited RAM capacity, one of the 8 memory registers available was reserved for the t-register, but the other 7 were only available if programming was abandoned. By exchanging one memory register for 8 program steps, the calculator’s maximal program length was 48 steps (with only one storage register).
Manufactured from 1982 onwards, the TI-57 LCD, like the machines of the era, is made with the classic Klixon keyboard, but due to incorrect material selection, the quality of the machines deteriorated steadily, while in 1984 the manufacturer decided that — as with the basic machines —, the scientific models will be redesigned to use the reliable rubber membrane keyboard, which have been proven in Japanese calculators for many years. A portion of these two models (TI-55-III, TI-57-II), available since 1985, have been made in Taiwan due to further rationalization of production.
A small series of Italian TI-57 LCD in 1983-84, and TI-57-II in 1985 was assembled in Hungary at Híradástechnika Szövetkezet (Telecommunication Cooperative) and marketed under the original type designation, but with the label "Assembled in Hungary".
Manufacturer: | Texas Instruments (USA/Italy) |
Mfg. date: | 1983-84 |
Size: | 7,8×14,6×2,4 cm |
Weight (ready for operate): | 108 g |
Type: | programmable scientific |
Capacity: | 8/8+2 digits (input/display) 11/11+2 digits (internal precision) |
Operating logic: | AOS |
CPU: | Texas Instruments TP0456 vagy CD4572 + CD4555 |
Registers: | 3 standard (with saving the pending operation) 15 bracket maximum of 7 memory (with aritmetic) |
Features: | +/-change sign (direct entry of negative numbers) Ffloating-point notation Fixfixed-point notation: the listed decimals can be chosen (0-7) Sciscientific (exponential) notation Sqrsquare root x2square pivalue of pi (3.1415..) can be recalled 1/xreciprocal trigtrigonometrical functions (sin, cos, tan and inverses: arcsin, arccos, arctan) DMS-DDconversion of decimal and sexagesimal numbers logexponential and logarithmical functions (10- and e-base) yxraising to power P-Rconverting coordinates between rectangular and polar systems n!factorial |
Display: | 8+2+2 digit LCD |
Power: | 2×LR44 button cell |
Programming method: | merged keystroke-programmable |
Program capacity: | maximum of 48 steps |
Test results: | trigonometry:result of sin-1(cos-1(tan-1(tan(cos(sin(60°)))))), reference value: 60. 60.019845215 exponential:result of 0.999160000, reference value (first 14 digits): 3.0068804206375×10-70 3.006920635E-70 |