HP-49 series

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(Redirected from HP-49G Plus)

The HP-49G series are Hewlett-Packard (HP)-manufactured graphing calculators. They are the successors of the HP-48 series, one of the best-selling calculator ranges among engineers, scientists, and students.

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Specifications

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HP-49G

The 49G has algebraic (default) and RPN entry modes, and is based on a 4MHz HP Saturn processor.

The calculator is often compared to the Texas Instruments TI-89, which is targeted more towards classroom use and employs a drastically faster CPU. Speed of calculation varies between the two calculators for each particular problem, but generally the TI-89 CAS (based on Texas Instruments' Derive engine) outperforms that of the 49G (in areas such as simultaneous equation solving, integration, and matrix manipulation), though the 49G is faster in other areas – notably 3D plot generation and series expansion. A rare comparison is of this calculator to computer software such as Maple. The HP49 has the ability to solve many equations symbolically that come up in circuit analysis that Maple is incapable of solving.

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Basic characteristics

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HP49G+

The HP 49G+ (sometimes written HP 49G Plus) features an entirely new processor architecture, both USB and IrDA (infrared) communication, memory expansion via an SD card, and a slightly larger screen, as well as other improvements over previous HP-48/49 models. It is worth noting that the calculator software does not run directly on the new ARM processor, but rather on an emulation layer for the older Saturn processors; this allows the 49G+ to maintain compatibility with many of the programs written for other HP-48/49 calculator models. Despite the emulation, the 49G+ is still much faster than any other model of HP calculator currently available, and it is possible to run programs written in assembly language directly on the ARM. A port of the GNU C compiler is also available.

Another model exists, the HP 48GII. At first glance it appears to be an improved HP-48G, but it is really a low-cost version of the 49G+. It has no user-available flash ROM or SD card storage, approximately 80 kB of user-available RAM, and a slightly smaller screen compared to the 49G+. The ROM used is identical to that used in the 49G+. Because of this, many users have taken to calling it the "49G-" as a joke.

The 48GII will run most programs compatible with the 49G+ provided that there is enough memory.

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Basic characteristics

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Programming

The HP-49 series of calculators support a stack-based programming language named Reverse Polish Lisp (RPL), a combination of Reverse Polish Notation (RPN) and Lisp. RPL adds the concepts of lists and functions to stack-based programming, allowing the programmer to pass unevaluated code as arguments to functions, or return unevaluated code from a function by leaving it on the stack.

The highest level language is User RPL. Every User RPL command checks the stack for certain arguments and returns an error if they are not present. Below User RPL is System RPL (SysRPL). Most System RPL commands have no argument checking, making System RPL programs dramatically faster than User RPL ones. In addition, System RPL provides many advanced functions that are not available in User RPL. System RPL programs can be created without the use of PC software (although it is available), thanks to the calculator's excellent builtin compiler, MASD. MASD also can compile Saturn ASM and with the latest ROM revision for the 49g+, ARM ASM on the calculator iteslf. Many tools exist to aid programmers and make the calculator a powerful programming environment.

Saturn ASM, and, on the 49G+, ARM ASM and C, are also available using desktop based compilers.

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HP-GCC for the 49G+

HP-GCC is an implementation of the GCC compiler, released under an LGPL licence. It is now mainly targeted at the ARM based 49G+ calculator. Previous versions of HP-GCC supported the other ARM based calculator models, but this was removed due to lack of interest and compatibility issues.

The latest version of HP-GCC offers many enhancements from earlier versions. Most notably is that the compiled code is now ARM thumb by default resulting in great reductions in code size with little performance hit. Besides implementing of most ANSI C, there are device-specific libraries that allow access to things like the calculator's RPN stack, memory and piezoelectric buzzer.

Linux and Windows versions are available for download. The Windows version also includes a version of Programmer's Notepad for a basic IDE.

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Issues, bugs and criticism

There have been some issues regarding the HP 49G+. Many of these have been solved or greatly improved upon with subsequent production runs.

Some users have reported that the plastic key hinges are flimsy and break within a few months. Newer keyboards generally feel much nicer and are more durable, but this continues to be a problem for some users. Typing style may play a role in keyboard breakage.

Another main complaint is poor documentation. The writing quality is below average and important topics are not covered in depth. A new Advanced Users Guide does much to correct this problem. At almost 700 pages, it contains detailed programming instructions, a complete command reference, and many other advanced topics.

Users have reported spurious alarms and missing keypresses. The keyboard handler was rewritten in ROM 2.00. The new handler does not miss keystrokes in software but has poor debouncing.

Initially there was a problem with battery life, but an upgrade of the system ROM has fixed that.

The current ROM version can be determined by the command VERSION. The most recent version at the time this was written was 2.01, which should report as: 

"Version HP49-B
 Revision #2.01-2"
"Copyright HP 2005"

If the version is not most recent, it should be updated. A current ROM and installation instructions can be found at HP's 49G+ homepage (see external links).

On Amazon, the average rating for HP 49G+ is 2.5 on a scale of 1 to 5, versus 4.5 for its predecessor HP-48GX and 4.5 for its competitor TI-89. Keep in mind however, that many of those reviews are from old units that had many problems, and newer users are generally quite satisfied with build quality. Used HP-48GX calculators are 2-3 times more expensive than new HP 49G or HP 49G+, and whilst the HP 49G/G+ is decreasing in price, the used 48GX's are actually increasing in value.

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External links

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