Texas Instruments TI-65
Datasheet legend
Ab/c:
Fractions calculation
AC: Alternating current BaseN: Number base calculations Card: Magnetic card storage Cmem: Continuous memory Cond: Conditional execution Const: Scientific constants Cplx: Complex number arithmetic DC: Direct current Eqlib: Equation library Exp: Exponential/logarithmic functions Fin: Financial functions Grph: Graphing capability Hyp: Hyperbolic functions Ind: Indirect addressing Intg: Numerical integration Jump: Unconditional jump (GOTO) Lbl: Program labels LCD: Liquid Crystal Display LED: Light-Emitting Diode Li-ion: Lithium-ion rechargeable battery Lreg: Linear regression (2-variable statistics) mA: Milliamperes of current Mtrx: Matrix support NiCd: Nickel-Cadmium rechargeable battery NiMH: Nickel-metal-hydrite rechargeable battery Prnt: Printer RTC: Real-time clock Sdev: Standard deviation (1-variable statistics) Solv: Equation solver Subr: Subroutine call capability Symb: Symbolic computing Tape: Magnetic tape storage Trig: Trigonometric functions Units: Unit conversions VAC: Volts AC VDC: Volts DC |
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Texas Instruments TI-65
A surprisingly interesting calculator, this TI-65. Its shape is reminiscent of other "Galaxy" series calculators, like the TI-66. Its buttons look like the buttons on more modern TI calculators, such as the TI-68. Its features, however, are unlike any TI machine I've seen before.
No, nothing dramatic here, just a curious mixture of the old and the new.
This is a keystroke programmable calculator, but a rare kind in TI's lineup; a machine with a fully merged programming model. Most 2-3 keystroke sequences count as a single instruction in program memory. The size of program memory is quite decent; 100 fully merged program steps can be used for many things.
The calculator also has many advanced programming features, including conditional branching, labels, and subroutines. It also has a DSZ loop instruction. It also has a built-in numerical integration capability that evaluates the integral of a function implemented in the form of a user program.
But perhaps the most unusual feature on a programmable TI calculator is an HP-55 style up-down timer (albeit with only a 1-second resolution). The timer is started using the TUp or TDn buttons; while the timer is running, it is possible to perform other calculations, or keeping the timer on the display, it is possible to save "lap times" into memory registers by simply pressing the appropriate register's number.
The following program example uses iteration to accurately compute the logarithm of the Gamma function using a modified version of Stirling's formula, for any argument, including negative arguments whose integer part is odd (e.g., -3.5):
2nd 53.53 00 LBL F1 12.0 01 STO 0 1 02 1 12.1 03 STO 1 2nd 53.0 04 LBL 0 5 05 5 3rd 42 06 x<m 0 07 0 2nd 54.1 08 GTO 1 13.0 09 RCL 0 12.38 10 STO× 1 11 1 1 12 1 12.59 13 STO+ 0 14 0 2nd 54.0 15 GTO 0 2nd 53.1 16 LBL 1 13.0 17 RCL 0 38 18 × 32 19 LN 49 20 - 13.0 21 RCL 0 49 22 - 13.1 23 RCL 1 32 24 LN 59 25 + 16 26 ( 2 27 2 38 28 × 2nd 17 29 π 28 30 ÷ 13.0 31 RCL 0 17 32 ) 33 33 √ 32 34 LN 59 35 + 16 36 ( 16 37 ( 16 38 ( 16 39 ( 9 40 9 9 41 9 34 42 1/x 28 43 ÷ 13.0 44 RCL 0 2nd 33 45 x2 49 46 - 1 47 1 4 48 4 0 49 0 34 50 1/x 17 51 ) 28 52 ÷ 13.0 53 RCL 0 2nd 33 54 x2 59 55 + 1 56 1 0 57 0 5 58 5 34 59 1/x 17 60 ) 28 61 ÷ 13.0 62 RCL 0 2nd 33 63 x2 49 64 - 3 65 3 0 66 0 34 67 1/x 17 68 ) 28 69 ÷ 13.0 70 RCL 0 2nd 33 71 x2 59 72 + 1 73 1 17 74 ) 28 75 ÷ 1 76 1 2 77 2 28 78 ÷ 13.0 79 RCL 0 39 80 = 2nd 52 81 RTN