RTC or real-time clock is a kind of computer clock for keeping track of the recent or most current time. Commonly, RTCs are present in almost all or any device, which are electronic in nature that needs to keep time accurate. Meanwhile, temperature sensors are devices that gather data concerning the temperature from a source and convert it to a form that can be understood either by an observer or another device. These sensors can be in various forms and are used for a wide variety of purposes, from simple home use to extremely accurate and precise scientific use. They play a very important role almost everywhere that they are applied; knowing the temperature helps people to pick their clothing before a walk outside just as it helps chemists to understand the data collected from a complex chemical reaction.
The circuit uses a PCA8565 CMOS real time clock and calendar optimized for low power consumption. A programmable clock output, interrupt output and voltage-low detector are also provided. All address and data are transferred serially via a two-line bidirectional I2C-bus with a maximum bus speed of 400kbit/s. The built-in word address register is incremented automatically after each written or read data byte. It also includes a MCP9801 digital temperature sensor capable of reading temperatures from -55°C to +125°C. Temperature data is measured from an integrated temperature sensor and converted to digital word with a user selectable 9 to 12 bit Sigma Delta Analog to Digital Converter. The MCP9801 notifies the host controller when the ambient temperature exceeds a user programmed set point. The ALERT output is programmable as either a simple comparator for thermostat operation or as a temperature event interrupts. Communication with the sensor is accomplished via a two-wire bus that is compatible with industry standard protocols. This permits reading the current temperature, programming the set point and hysteresis and configuring the device. Address selection inputs allow up to eight MCP9801 sensors to share the same two-wire bus for multizone monitoring. Small physical size, low installed cost and ease of use make the MCP9801 an ideal choice for implementing sophisticated temperature system management schemes in a variety of applications.
The board is basically a carrier for the two IC’s that make up the Real Time Clock (RTC), PCA8565 and the Digital Temperature Sensor, MCP9801. It conveniently combines the two for applications that require RTC and temperature sensing. A particularly useful feature of this RTC is that it can detect power down and record the time at that event. This is ideal for connecting to a microcontroller that does not have an RTC.
I2C Temperature Sensor & Real Time Clock - [Link]
8 Channel Relay Board is a simple and convenient way to interface 8 relays for switching application in your project. Input voltage level support TTL as well as CMOS. Easy interface with Microcontrollers based projects and analog circuits.
8 Channel Relay Board - [Link]
By Richard Moss @ gizmag.com
Researchers at Rice University’s Laboratory for Nanophotonics (LANP) have developed a new image sensor that mimics the way we see color by integrating light amplifiers and color filters directly onto the pixels. The new design enables smaller, less complex, and more organic designs for CMOS (complementary metal-oxide semiconductor) sensors and other photodetectors used in cameras.
Conventional image sensors work by first converting light into electrical signals, then combining that information with the red, green, and blue color data determined by separate filters (or, especially in low-end cameras, a single filter array that uses a mosaic pattern to interpret colors). But this approach adds bulk to the sensor, and the filters gradually degrade under exposure to sunlight.
Nature inspires color-sensitive, CMOS-compatible photodetector - [Link]
by Nancy Owano @ phys.org:
Sony’s advance in image sensors appears quite natural: the company has developed a set of curved CMOS image sensors based on the curvature of the eye. A report on the sensors in IEEE Spectrum said that, “in a bit of biomimicry,” Sony engineers were able to achieve a set of curved CMOS image sensors using a “bending machine” of their own construction.
Sony inspired by biomimicry develops curved CMOS sensors - [Link]
On Semiconductor have introduced a highly integrated CMOS modem for applications running the Highway-Addressable, Remote Transducer (HART) communication standard for field instruments and masters. The NCN5193 requires minimal external passive components to provide the functions needed to satisfy HART physical layer requirements including modulation, demodulation, receive filtering, carrier detect, and transmit-signal shaping.
The NCN5193 also has an integrated DAC for low-BOM current loop slave transmitter implementation and employs phase-continuous frequency shift keying (FSK) at 1200 bits per second. To conserve power the receiver circuitry is disabled during transmit operations and vice versa. This meets the requirements of half-duplex operation used in HART communcations.
Integrated CMOS HART Modem - [Link]
Stacking memory is just most obvious application of this ultra-cheap method of stacking 3D circuitry within the metallization layers of standard CMOS chips, but I’m sure that when designers put on their thinking cap they’ll find many more useful applications.: R. Colin Johnson @NextGenLog
Chips On-the-Cheap Funded by SRC – [Link]
The PCA9508 is a CMOS integrated circuit that supports hot-swap with zero offset and provides level shifting between low voltage (down to 0.9 V) and higher voltage (2.7 V to 5.5 V) for I2C-bus or SMBus applications. While retaining all the operating modes and features of the I2C-bus system during the level shifts, it also permits extension of the I2C-bus by providing bidirectional buffering for both the data (SDA) and the clock (SCL) lines, thus enabling two buses of 400 pF. Using the PCA9508 enables the system designer to isolate two halves of a bus for both voltage and capacitance, and perform hot-swap and voltage level translation. Furthermore, the dual supply pins can be powered up in any sequence; when any of the supply pins are unpowered, the 5 V tolerant I/O are high-impedance.
PCA9508 has B-side and A-side bus drivers. The 2.7 V to 5.5 V bus B-side drivers behave much like the drivers on the PCA9515A device, while the adjustable voltage bus A side drivers drive more current and incur no static offset voltage. This results in a LOW on the B-side translating into a nearly 0 V LOW on the A side.
The hot swap feature allows an I/O card to be inserted into a live backplane without corrupting the data and clock buses. Control circuitry prevents the backplane from being connected to the card until a stop command or bus idle occurs on the backplane without bus contention on the card. Zero offset output voltage allows multiple PCA9508s to be put in series and still maintains an excellent noise margin.
- PCA9508D CMOS integrated circuit (3 units)
- BUS Master
- Slave 400kHz (3 units)
- 10kΩ Resistor (6 units)
- Ground Source
Hot swap level translating I2C repeater - [Link]
This Design Idea describes a simple two-chip CMOS circuit that can sort capacitors into 20 bins over a wide range (100pF to 1μF), using 10 LEDs to display the value range. The circuit is power efficient and can be run using two CR2032 cells. As such, it can be built into a handheld probe. by Raju Baddi
Simple capacitance meter bins parts - [Link]
With the rapid development of GPS (Global Positioning System) techniques, GPS gets wider application in many fields. GPS has features such as high precision, global coverage, convenience, high quality, and low cost. Recently, the use of GPS extends speedily from military to civilian applications such as automobile navigation systems which combine the GPS system, e-map, and wireless network. GPS is getting popular, and the market for GPS techniques is extending continuously.
UARTs provide serial asynchronous receive data synchronization, parallel-to-serial and serial-to-parallel data conversion for both the transmitter and receiver sections. These functions are necessary for converting the serial data stream into parallel data that is required with digital systems. Synchronization for the serial data stream is accomplished by adding start and stop bits to the transmit data to form a data character. Data integrity is ensured by attaching a parity bit to the data character. The parity bit is checked by the receiver for any transmission bit errors.
The circuit describes how to combine GPS into a navigation system by using a Philips 2-channel UART, the SC16C2552B. The SC16C2552B is a two channel Universal Asynchronous Receiver and Transmitter (UART) used for serial data communications. Its principal function is to convert parallel data into serial data, and vice versa. The UART can handle serial data rates up to 5 Mbit/s.
- SC16C2552BIA44 Dual UART, 5 Mbps (max.), with 16-byte FIFOs
- 80C51 CMOS 0 to 42 MHz Single-Chip 8 Bit Microcontroller
- 12 MHz Oscillator Clock
- 1.8432 MHz Oscillator Clock
- 22pF Capacitor – 2 Units
- 33pF Capacitor – 2 Units
- 0.1µF Capacitor – 2 Units
- 10 µF Capacitor – 2 Units
- 74LV04 Hex Inverter – 2 Units
UART in GPS navigation system – [Link]
by Steven Keeping:
LEDs have many advantages over traditional lighting including efficacy, longevity, and robustness, but price is not one of them.
The reason why LEDs are expensive is partly because the manufacturing process used to fabricate the wafers from which the individual chips are cut is difficult and employs exotic materials such as gallium nitride (GaN) deposited on sapphire or silicon-carbide (SiC) substrates.
But recently, some manufacturers have proposed using silicon, the material routinely used to fabricate billions of integrated circuits (ICs) every year, as an LED substrate. Apart from potentially reducing the cost of LEDs, the use of mature complementary metal oxide semiconductor (CMOS) IC technology would allow fabrication in conventional wafer fabs that have spare capacity.
Will Silicon Substrates Push LED Lighting Into the Mainstream? - [Link]