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Archive for October 29th, 2010

Review of the TI-84 Calculator – Part I

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How to impress a kid

After playing with a virtual TI-84 calculator (read the posting) and with Xmas coming up I thought that a (real) TI-84 calculator would make a fine gift for a kid who will be going to college next year.  You can pick up a TI-84 Plus Silver Edition calculator for $115 on – no tax and free shipping.

I often wonder about the quality control of these calculators.  So as not to disappoint the recipient of this gift I decided to do a little QA testing.  Using an X-Acto knife you can carefully cut around 3 of the 4 sides of the blister pack that hermetically seals this calculator.  The blister pack is a clam shell once you get the welded plastic cut free.  If you are careful, you an put all the contents back, seal the clam shell  and no one will ever know.  Especially, in the heat of the Xmas gift-opening battle.

The by-product of QA testing is that you can become quite knowledgeable of the product.  Won’t that teen or pre-teen kid be impressed with the knowlege an adult has of these new fangled calculators?  “Here, let me show you how it work’s”.

What you get

Well, you get everything you see above.  You get the calculator, 4 decent AAA batteries (Duracell), two USB cables for file transfer, a CD full of software, and a Quick Start Guide.  Two USB cables are provided – one for connecting two calculators and the other for connecting the calculator to a PC.


I have not bought anything more than a $12 calculator over the past 20 years.  So, if you have fallen behind – as I have – on modern calculator technology, here is what’s new over the past 20 years and the advantage of these modern calculators over the $12 Wal-Mart special.

  1. Flashable Operating Systems.  The OS on the TI-84 and similar model calculators have an upgradable operating systems.  This means that once you have the underlying physical hardware (the physical calculator) you can layer on the factory operating system plus any upgrades to the OS that the vendor provides.
  2. Replaceable face plate to redefine keys for upgraded OS.  Each key on the calculator has about three functions.  The two additional functions other than what is stenciled on the key, accessed by pressing the 2nd key or the ALPHA key, gets you more functions.  The two additional functions are on the removable face plate.  This means that a new faceplate can be provided along with a new OS.  That is, if the OS provides new function the vendor can provide you the new OS plus a new faceplate that redefines any of the keys consistent with the new OS.  So, this strategy preserves, in some sense, your investment IF the vendor continues to upgrade and enhance the operating system over time.
  3. Real CPU’s.  The TI-84 is based on the Zilog Z80 chip.  This is a 8-bit processor similar to the Motorola 6502 that dates way back to the late 1970’s.  Believe it or not, this chip is still in wide use.  You can read more about the Z80 here.
  4. It’s programmable in BASIC and Z80 Assembler.  So, what you have in this modern calculator is an execution platform for running programs written in TI-BASIC and Z80 assembler language in addition to the native functionality of the base calculator.  There is plenty of support for software development from Texas Instruments as well as the TI Hacker community.  Using a PC-based TI-84 emulator and a development system you can write BASIC and Assembler plus debug it on a PC before you even load it on to a real calculator.  Some of the available emulators have decent debuggers where you can single step and watch Z80 assembler code run and inspect registers, memory as you go.
    Read the rest of this entry »

Written by frrl

October 29, 2010 at 3:08 am

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