Hp 39g+

HP 39/40 series
Company type	Product line
Industry	Electronics, Calculators
Predecessor	HP 38G
Founder	Hewlett-Packard
Products	Graphing calculators
Owner	Hewlett-Packard

HP 39/40 series represents a line of graphing calculators developed by Hewlett-Packard, following the HP 38G model. This collection comprises six variants that provide algebraic input methods and facilitate numeric computations, with differing extents of symbolic calculation support. Designed primarily for secondary education students, these calculators enable the transfer of APLETs or E-lessons through cable or infrared connections, thereby enriching mathematical learning via graphical and numerical investigation.

HP 39g

Introduced in 2000, the HP 39g (F1906A) includes the following specifications:

CPU: 4 MHz Yorke (Saturn architecture)
Connectivity: Proprietary infrared interface and serial RS-232 port
Memory capacity: 256 KB RAM
Display: 131 × 64 pixel resolution
Comes with a protective hard cover
Offers limited symbolic equation processing features

HP 40g

Launched concurrently with the HP 39g in 2000, the HP 40g (F1907A) operates on the same system software but differs in hardware and application capabilities. It shares hardware components with the HP 49G/39G series, including a rubber key design, and incorporates the sophisticated computer algebra system (CAS) from the HP 49G, known as HP CAS. The HP 40g provides a simplified mathematical analysis environment without intricate flags, lacks infrared connectivity, and restricts users to managing 27 variables. Its solver is basic, limiting its suitability for advanced tasks. The HP 40g is prohibited on several standardized exams such as the ACT, but has been allowed on the SAT since 2019.

Notable features include:

Hardware similar to HP 39g except:
Communication: No infrared support; includes serial RS-232
Software: Equipped with an equation editor and advanced CAS

HP 39g+

The HP 39g+ (F2224A), released in September 2003, enhances performance through:

CPU: 75 MHz Samsung S3C2410X (ARM920T core)
Memory: 256 KB RAM and 1 MB flash storage
Connectivity: USB Mini-B port supporting Kermit or XModem protocols, plus IrDA infrared
Power source: Three AAA batteries with CR2032 backup battery
Display resolution: 131×64 pixels
Does not include a hard cover
Symbolic equation capabilities remain limited

Although based on an ARM processor, its operating system simulates the Saturn CPU at an accelerated speed while omitting the CAS functionality found in the HP 40G’s OS.

HP 39gs

Released in June 2006, the HP 39gs (F2223A) is equipped with a Samsung S3C2410A (ARM920T core) CPU running at 75 MHz, alongside 256 KB RAM and a flash memory of 1 MB. It supports diverse communication methods including USB Mini-B (compatible with Kermit and XModem protocols), IrDA infrared, and a four-pin asynchronous serial port operating at 3.3 V TTL levels (RS-232 available via adapter). Powered by four AAA batteries plus a CR2032 backup cell, it features a display resolution of 131×64 pixels and comes with a hard cover. The calculator offers limited symbolic equation support and its flash memory enables firmware updates. Despite utilizing an ARM processor, its OS emulates the Saturn chip to deliver improved speed compared to the earlier HP 39g model.

HP 40gs

Introduced in mid-2006, the HP 40gs (F2225A) is built on the same hardware foundation as the HP 39gs, utilizing a 75 MHz Samsung ARM processor. However, it features double the flash memory at 2 MB to accommodate more sophisticated CAS software. While it does not support infrared communication, it includes an equation writer and enhanced computer algebra system functionality.

HP 39gII

The HP 39gII (NW249AA), launched in October 2011, incorporates an upgraded 80 MHz Freescale STMP3770 ARM926EJ-S processor. It offers 256 KB of RAM alongside a sizable 128 MB of flash storage, with approximately 240 KB RAM and between 80 to 105 MB flash available for user applications. The device is equipped with a high-resolution monochrome display (256×128 pixels) and supports USB On-The-Go through a Micro-AB port. Its BCD mathematics libraries were redeveloped in platform-independent C code to enable native execution rather than emulation. The calculator’s programming language, resembling Pascal, serves as a forerunner to the HP Prime’s HP PPL. Additional features include a 128-level stack and Unicode (UTF-16) support. Two versions exist with minor differences in key labeling.

An advanced "HP 39gII+" model featuring CAS was nearly finalized but ultimately discontinued after Freescale ceased production of the processor. This prompted HP to reimagine the design, which led to the introduction of the more capable, color touchscreen HP Prime in 2013.

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