Simplify I2C Electrical Validation and Protocol Decode Using Software

Overview of I2C Bus:

In early 1980s Philips Semiconductor developed a simple bidirectional 2-wire bus for efficient inter-IC control. This bus is called Inter IC or I2C bus. All I2C Bus compatible devices incorporate an on-chip interface which allows them to communicate directly with each other via the I2C -bus.

The I2C’s physical two-wire interface consists of a bi-directional serial clock (SCL) and data (SDA) lines. Each device that is connected to the bus is software-addressable by a unique address and simple master/slave relationship with the bus exists all the time. I2C is a serial, 8-bit oriented, bi-directional data transfers can be made at 100Kbits/s in the standard mode, up to 400Kbits/s in the Fast mode, up to 1Mbits/s in fast Mode plus, or up to 3.4Mbits/s in the high speed mode. On-chip filtering rejects spikes on the bus data line to preserve data integrity.

Phillips Semiconductor (now NXP Semiconductors) has published electrical specifications and protocol specification since 1982. The recent I2C- bus specification and user manual was published in year 2007. By following the electrical and protocol specification in the I2C document, semiconductor design and manufacturing companies can ensure interoperability of ICs using I2C Bus.

I2C protocol overview:

Typical data transfer between two ICs using the I2C interface is as shown:

All transactions start with START Condition and stop with STOP condition In I2C Bus. These two conditions are controlled by the master IC. The typical I2C frame format has the following contents: START, address, read/write, data followed by ACK/NACK, and STOP condition at end of the operation.

START: A condition where high to low transition of SDA line occurs when SCL is held high. The is initiated by the master IC.

Address: Master sends the slave the 7- bit or 10- bit address of the slave device

Read/write: The slave address is followed by this bit. A ZERO indicates a transmission (write), and a ‘ONE’ indicates a request for READ.

Acknowledge (ACK) and Not Acknowledge (NACK): This takes place after every byte. During this condition the transmitter releases the SDA line during the acknowledge clock pulse so that the receiver can pull the SDA line LOW, and the SDA line remains stable LOW during the HIGH period of this clock pulse.

When SDA remains HIGH during this 9thclock pulse, this defined as the Not Acknowledgement signal. The master can then regenerate either a STOP condition to abort the transfer or a repeated START condition to start a new transfer.

Data is an integer number of bytes read or written into device.

STOP: A condition during SDA transitions from LOW to HIGH when SCL is held high indicating the end of transfer of data.

I2C Electrical Measurements:

For successful interoperation of IC using I2C bus, the electrical characteristics of physical layer signals of I2C SCL and SDA signals should be compatibility. The timing between the master and slave devices should be within electrical specifications defined in the I2C Specification by NXP Semiconductor.

Electrical Measurement Challenges:

During electrical validation of I2C bus, test engineers need to ensure the I2C bus should comply with electrical parameters of I2C Bus. The challenges faced while electrical validation of I2C bus as follows:

• Test/Design Engineer must know I2C Protocol behaviour at physical layer of I2C Bus

• Electrical parameter measurements must be carried out at different protocol state ( example; stop bit, ack bit and so forth)

• Reference level for each of the measurement changes based on the rising or falling edge of the I2C signal transition

• Reference level is either 30% or 70% as against normally used reference level of 10% to 90% or 20% to 80%

• Validation is time consuming

Overall, measuring I2C electrical measurements demands a very high level of expertise in I2C phy layer behaviour, protocol layer, signal acquisition in oscilloscope and I2C Electrical measurement procedures. Due to complexity in I2C Electrical measurements, the results can be prone to errors.

Simplifying I2C Electrical Measurements using PGY-I2C Electrical validation and Protocol Decode Software:

The PGY-I2C Electrical Validation and Protocol Decode Software offers electrical measurements and protocol decoding as specified in Rev 03, June 2007 I2C Bus specification. Now design and test engineers can automatically make accurate and reliable electrical measurements and decode protocols in PGY-I2C software using data acquired by Tektronix DPO5000, DPO7000, DPO/DSA/MSO70000 series oscilloscope to reduce the development and test cycle.

PGY-I2C Software runs inside Tektronix oscilloscopes. During the run operation of the application, PGY-I2C sends commands to acquire to SCL and SDA signals of I2C bus. For accurate measurements, the recommended oscilloscope setup is:

• Signal is at least 5 to 6 six main vertical divisions in the oscilloscope display with the appropriate volts per division

• Select the appropriate volts per division to display the signal with at least 5 or 6 main vertical divisions

• Select sample rate such that at least 8 to 10 samples present in the rising or falling edge of SCL and SDA signals

• Set record length such that at least two I2C frames are captured to make most of I2C signals.

The application makes each of the I2C electrical measurements in every possible I2C protocol state and displays the min, max and mean values. If mean value is within the limit specified, application shows ‘Pass’. But in case, if the mean value is pass but either the min or max values exceed the limits, applications shows ‘pass*’ with asterisk.

PGY-I2C makes all these measurements in an instant of time addressing all the challenges of I2C electrical measurements, giving accurate and reliable measurements.

The ‘Detail View’ in the Analyze pane offers protocol information and measurement for each I2C Packet. This would help in debugging I2C bus in a system. In a master-slave I2C bus, different ICs would communicate. There is possibility of interoperability issues between IC s using I2C Bus. This problem could be due following reasons.

• Problems due to signal integrity in PCB

• EMI/EMC issues

• Not strict compliance to electrical characteristics of I2C Standard specification

The ‘Detail view’ would help in isolating interoperability issues by providing physical layer waveform, electrical measurements for each I2C message/frame and protocol decode.

Detail view contains following information:

• Waveform plot of the acquired data

• Protocol Decode in I2C packet/frame or I2C message format

• Electrical measurements for each I2C message or I2C packet/frame

• Selected I2C message or packet/frame waveform plot with protocol decoded data overlapped on the waveform

• Utility features such as cursors, cursor time readout, zoom, undo, fit to screen and pan

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Fight Climate Change and Global Warming Through the 3 Rs – Recycle, Reuse and Reduce

Don’t throw your appliances away! Recycle your electronic appliances at home and help save our environment.

That’s simple. Know the 3Rs: recycle, reuse and reduce. Here’s what you should know. Electronic appliances are made of ICs and other semi-conductors. Some of them, like the blender, water heater, and others, are just made of simple transformers and capacitors. If you know the basics of consumer electronics, you can do simple repair at home. These semi-conductors are just inserted in sockets in PCBs or printed circuit boards. You can even assemble them at home. But don’t think about that for now. Here are facts I’m laying down. These facts are interconnected with climate change and global warming. Remember, if you throw your appliances away, you are helping increase the intense heat that we are experiencing right now.

More appliances manufactured by businesses means more garbage. Recycling helps in reducing carbon dioxide emissions.

Do you know how a television set was made? I’m particularly interested on the TV because for others it seems really ordinary, yet intriguing, or even impossible. And personally, I’ve spent years mastering the workings of a television electronic circuit. Like you, I was really puzzled from the start.

How did that TV newscaster’s personality and voice ever enter into that tube and speaker when I just bought this little thing from an appliance store? Everybody who is not familiar with an electronic circuit will ask the same question. How did the voice and picture enter the television? It’s not an illusion. It’s not magic. It’s simple electronics applied scientifically.

The voice or the sound signal enters the components through the micro and milli-volts in small transformers inside. So do with the picture signal – it enters the picture section of the television through the super-small voltages inside.

How does a television set work? I’m going to simplify this question so it would be very easy for a novice or anyone like who hasn’t gone to a vocational school. I’ve spent years repairing and “rebuilding” electronic appliances in my small shop in my community. I’m careful not to throw the parts that I have “dissected” from inside the electronic appliances so as not to aggravate environmental degradation in my community. And with the countless television sets and electronic appliances that I have repaired and recycled, I have done a bit in fighting climate change and global warming.

You see, those appliances become “monsters” once you throw them away. They are made of plastic and chemicals harmful to the surrounding, our garden and the atmosphere.

Appliances in our home operate with semi-conductors, transistors, capacitors, resistors, and complex ones like ICs or integrated circuits. New brands of television and other electronic appliances are made up of ICs inside that they can be mass-produced and manufactured by hundreds of thousands. You can just imagine how this can affect the environment.

How can we help in reducing the manufacture of appliances? Or you may ask, how can you recycle if you don’t know how to repair? By just knowing the simple details inside the television set and other electronic appliances, you can have simple repair. By knowing how to repair a busted fuse, you are helping the environment. By orienting yourself of the semi-conductors, transistors, capacitors, resistors and ICs, you are preserving our environment. Right away, buy yourself a multi-tester and learn to use it. There are instructions inside on how to use a multi-tester. If not, watch out for my simple basics in electronics. I’m offering it for free.

Also, know the basics of electronics, such as a power supply. All electrical and electronic appliances have a power supply. This is the heart of the working appliance. It is connected to the power cord and into the electrical outlet in your home. To me, this is very simple, but for you, some basic can help you get started. There’s only one word that you have to know before anything else – safety. Then read and read.

I can provide you with the readings and the basics of recycle, reuse and reduce.

Sky Is the Limit With Pantech Sky A840S

The South Korean mobile manufacturer, Pantech, is the third best-selling producer of mobile phones in South Korea. Although this brand might seem unfamiliar to some, it has actually been around the block since 1991 and has supplied phones for the two largest carriers in the US, Verizon and AT&T. Now, Pantech offers the world its new and innovative smartphone, Sky A840S, also known as the Vega S5.

Smartphones have been mushrooming every week or so. What then makes Pantech Sky A840S different? What makes it stand out? Let us take a closer look at what’s unique about this device and what it can offer.

Under the hood, this kickass machine has a fast dual-core Qualcomm Snapdragon MSM8960 processor clocking in at 1.5 GHz. It operates on Android 4.0 Ice Cream Sandwich. No surprise there but a Jelly Bean Operating System would have been more welcome. For storage, this handset comes with a 1 GB DDR2 RAM, 16 GB of internal memory, 16 GB of Cloud memory and an external memory slot that can accommodate up to 32 GB of data.

Aside from its 2G and 3G network, it offers 4G 850/1800 LTE. The 4G LTE connection is the latest in mobile telephony communications and is designed to deliver data speed rates of up to 100 MBit per second or 1 GBit per second. Ten times faster than 3G network. Internet junkies can experience faster multimedia streaming, video conferencing, data transfer and online gaming with this type of network.

So why would one say that sky is the limit when talking about this device? A 5-inch IPS 5-point Multitouch Screen gives you the edge when you browse the web and read e-books, emails and other documents. Sky is the limit when you surf and play games with a wider screen. It provides an improved smartphone experience. Wait, there’s more. Do you want quality images without logging a bulky camera with you all the time? Sky’s 13 megapixel autofocus rear camera will solve that problem for you. It is a smartphone and a dual camera phone rolled into one and not just a run-off-the-mill snapper but a top-calibre camera at that. It takes vibrant and solid quality pictures plus a 2 megapixel front-facing snapper for video calls and conferences.

By now, I reckon that you have found a liking for this phone. So purchase this phone now and you’ll discover endless of possibilities.