Texas Instruments MBA
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 MBA
For me, this calculator represented an unexpected surprise. I knew about it of course; it's not an uncommon model. What I didn't even suspect is that it is a programmable unit. Because of this, I had no interest in acquiring one. Fortunately, my wife didn't know this, which is why one day she came home with an MBA that she purchased for the grand total of 50 cents at a local thrift store.
Programmability is not the only interesting feature of the MBA. As Palmer Hanson (whose name is well known to readers of the the one-time TI calculator enthusiast newsletter, the TI PPC Notes) noted, it is probably the only business calculator that uses precedence logic (which TI called A.O.S).
The programming model of the MBA is very similar to that of the TI-55. There are no instructions for control transfer or conditional execution (note, though, that it is possible to contrive conditional loops using self-modifying code); program memory is a mere 32 program steps, executed sequentially. However, using a technique involving the reset button and the fact that programs halt on errors, it is possible to create simple loops, including the simple factorial program presented here. Note that except for the difference in keycodes, this program is identical to the factorial program I wrote for the TI-55.
00 51 STO 01 01 1 02 32 1/x 03 61 RCL 04 01 1 05 55 × 06 51 STO 07 00 0 08 43 ( 09 61 RCL 10 01 1 11 65 - 12 01 1 13 44 ) 14 41 RST