Lightning connector - Apple accessory

To put it straight forward, this is a type of customized connector used in Apple products. Like how we have USB micro AB type connector on all smartphones and tablets, apple products have their customized connector on their phones. Previous versions of iPad/iPhone used to have 30-pin connector which is replaced by 8-pin lightning connector.

The lightning connector and the old 30-pin connector (docking) are shown in the figures. the 30-pin connector carries power as well as signals and can be used for docking purposes. The 8-pin lightning connector can be inserted either side. 30-pin connector was used in Apple products till the 4th generation. The 30-pin docking connector carries Audio, USB, Fire wire and other control signals. 

Later versions started extending video over the connector dropping Fire Wire. The 5th generation of iPhone started using lightning connector. To use a 8-pin lightning connector with 30-pin docking connector, you must have a adapter.

Advantages of lightning connector:

1. Light and small compared to 30-pin connector

2. Lightning connector has a control chip on it which takes care of the direction even though connector is assigned in reverse.

3. Connectivity to various output types is easy by using adapters.

 4. Within a small pin out various outputs like audio, video and controls can be connected.

The pin out of 8-pin lightning connector is shown in the figure shown above.

5. Any signal in the pin out can be used for power which is very flexible.

6. Edge detection mechanism is used to detect a plug connected to the 8-pin connector.

Displays - Pixels - Part 1

Displays are part of everyday life. Be it our mobile screen, Television screen, PC screen, display forms a most important human interface. From the age old CRT displays to the latest OLED type displays, the display technology has been evolving day by day. Did we ever think of curved displays to be designed? Let us discuss about different display technologies and terminologies in series of articles.

Pixels on the screen:

Be it any display, the display arrangement is in the form of pixels. A single pixel is also called “Picture element”. The pixels are arranged in the x and y direction. The pixel information will be taken care by the operating system of the processor to which display is connected which helps to form an image on the screen.

1-bit/B&W displays:

1-bit displays are used to represent Black & White displays. Based on the bit value of 0 or 1, Black or white value is represented. 

8-bit/256-color displays:

8-bits of information are dedicated for each pixel which can vary up to 255 combinations. So, a 8-bit color displays can have up to 256 colors. These are used in color displays which came immediately after black and white displays.

24-bit/True color displays:

24-bits are used to represent each pixel on the screen. Each pixel uses 8-bit for R, G, B to form a color. This gives complete color information compared to 8-bit displays and are called true displays. Each pixel can represent up to 16M (16777215 in particular) colors.

RGB combinations:

The pixel color information will be a RGB model where the respective color of the pixel can be formed by the percentage of combination of RGB. Full percentage of RGB (255,255,255) represents a white where as the null combination of RGB (0,0,0) forms black.

Digital Living Network Alliance (DLNA)

Assume you have a mobile, TV, PC and multimedia devices at home and you would like to play a video taken from your camera over TV. Previously, you would have transferred the contents to DVD drive using PC, then play that DVD using some multimedia device. But think of a technology where you can play the videos from you camera directly connecting to TV. Yes, this possible using DLNA (Digital Living Network Alliance). DLNA helps various multimedia devices in the home to communicate between each other. DLNA was started by Sony.

Multimedia devices like TV, DVD/Blu-ray players, smart phones, tablets, PCs and other commercial devices can be part of this network. For this you only need a wireless/wired connection and a application installed on these multimedia devices.  The only requirement is both the devices must be DLNA compliant. DLNA defines standards like any other protocols.

In DLNA also, the same Client-Server architecture applies. If you want to transfer data from your PC, install softwares like Twonkyto make it a server. Also, TVersity is another example.  On the receiver side you have Smartshare, Allshare.

Except Apple all other smart phone vendors like Intel, HP, Motorola, HTC, Microsoft, Samsung, LG and Panasonic are making products that will happily communicate with each other. Apple uses AirPlay. This is just not a feature of android phones, NOKIA is bringing it to windows phones also.

You can detect a DLNA device by seeing a DLNA logo on the product you have purchased.

FPGA vs ASIC

FPGA - Field Programmable Gate Array

ASIC - Application specific Integrated circuit

FPGA is seen in many applications these days and many of us are aware of it. But we often here about ASIC which is confusing. ASIC is designed to be used for specific application where as FPGA is generic. Designers tend to use FPGA for initial development of their code and then order for ASIC for their final design. FPGA consumes less time in design cycle as the only challenge lies in selecting a suitable FPGA and then write your code. ASIC consumes more time to come to market as it has through cycles of making, floor planning, routing, timing analysis, verification and manufacturing. Let us study more differences between ASIC and FPGA from the below table.

DDR3 vs DDR4

The rate at which the memory technology (in terms of speed) is always higher compared to the counter parts around. Now that the DDR4 is sampled out, let us see differences between DDR4 and it's predecessor DDR3.

We will discuss in detail the implementation and technical details of DDR4 in future articles.

Using crystals in embedded applications - Part 3

In the previous articles, we have discussed about external components used around crystal for stable output frequency signal generation. We also, discussed about the load capacitance and how to match this load capacitance with the external reactance components. The input-output capacitance, output resistance determine the reactive components outside. Here are some few more points to be considered in this aspect:

• The internal CMOS inverter gate inside the processors/controllers and other main integrated circuits are generally operated in active region. The gate must be designed such that it must overcome loss in the external feedback resistor and frequency decisive components (Damping resistor, external load capacitance).
• As the CMOS inverter gate is operated as a linear amplifier, the characteristics like phase and propagation delay also to be considered.
• Just to throw a small a small light on CMOS inverter, it is a combination of P-MOSFET and N-Mosfet.

• The above circuit is nothing but a unbuffered inverter circuit.

Parameters to consider for crystal oscillator selection:

• Operating frequency
• Supply voltage (decides logic level)
• Operating temperature
• Storage temperature
• Tolerance/Stability
• Rise/Fall time
• Load drive capability (in terms of capacitance, pF)
• Desired output logic type
• RMS Jitter
• Start up time