Electronics News
Archive : 16 March 2007 год
At the heart of the DS2792's computing core is the low-power, 16-bit MAXQ20 microcontroller with its advanced, accumulator-based, 16-bit RISC architecture. Because the DS2792's instructions contain both the operation code and data, its fetch and execution operations are completed in one cycle without pipelining. The processing core is supported by a 16-level hardware stack, which enables fast subroutine calling and task switching. Data can be quickly and efficiently manipulated with three internal data pointers. Multiple data pointers allow more than one function to access data memory without having to save and restore data pointers each time.
To allow the user to program proprietary algorithms, the DS2792 contains three types of memory: programming memory, data EEPROM, and data RAM. The memory is arranged in a Harvard architecture, with separate address spaces for program and data memory. The 8k words of programming memory consists of 4k words of password-protected EEPROM and 4k words of ROM. The inclusion of EEPROM allows the devices to be reprogrammed, which simplifies and reduces the cost of development and field upgrades. The data EEPROM consists of 64 words and is available for storing important data such as charge parameters, cell characteristics, and manufacturing data that should remain unaffected by severe battery depletion, accidental shorts, or ESD events. The data RAM is 256 words and is used for temporary data storage.
The DS2792 also provides precise current, accumulated-current, voltage, and temperature measurements. Current measurements are internally summed to calculate the accumulated current, which is accurate to within 0.5% ±4.0µV over a range of ±64mV. Using a 15mOhm sense resistor, this current accuracy translates to within 0.5% ±267µA over a 4.2A range. The DS2792 measures voltage as a 10-bit value over a 0 to 4.99V range with a resolution of 4.88mV. An on-chip temperature sensor measures the temperature of the battery and reports the results as a 10-bit value with a resolution of 0.125°C. All measured data and any password-protected reprogramming of the EEPROM memory can be communicated to the host through the DS2792's UART interface.
Typical applications for the DS2792 include digital video cameras, SLR digital still cameras, sub-notebook and ultra-portable PCs, industrial PDAs, and handheld GPS devices. The DS2792 is available in an 8mm x 4mm, 28-pin, lead-free TDFN package. Prices start at $3.28 (1000-up, FOB USA).
Optional LogWare III supports Ethernet, 802.15.4 wireless, RS-232, email messaging services and as many “DewKs” as can be put on a network
Hart Scientific, a division of Fluke Corporation and the world leader in temperature calibration products and services, announces the new Hart Scientific 1620A paperless temperature and humidity data logger with wireless, Ethernet, and RS-232 communications.
Designed to facilitate the electronic management of environmental temperature and humidity data, this thermo-hygrometer is intended for environmental monitoring in critical locations such as calibration and research labs, pharmaceutical and chemical storage areas, and many medical environments.
Product information
The Model 1620A – the “DewK” – accepts inputs from up to two sensors, which may be mounted directly on the unit or remotely (up to 30 meters away). The DewK allows sensor hot-swapping and each sensor contains its own calibration data to prevent down time during calibration service. The 1620A comes with a NVLAP-accredited calibration.
Two sensor models are available. The “H” model reads temperature to ± 0.125 °C over its calibrated range of 16 °C to 24 °C. It measures humidity to ± 1.5 % RH from 20 % to 70 % RH. The “S” model reads temperature to ± 0.25 °C over its calibrated range of 15 °C to 35 °C. It records humidity to ± 2 % RH from 20 % to 70 % RH.
In addition to on-board memory which stores up to 400,000 date and time-stamped measurements, data collected by the Hart Scientific 1620A may also be sent directly to a PC in real time using the serial port, Ethernet, or optionally using 802.15.4 wireless communication. By adding Hart Scientific’s LogWare III software, you can simultaneously monitor an unlimited number of instruments. The Windows-based software enables statistical and graphical analysis of real-time or previously recorded data, and can send emails to PDAs, pagers, and mobile/cell phones when triggered by user-defined events.