Electronics FAQ

We have all used InfraRed based remotes to control various appliances around our house. All these remote work by transmitting data in form of flashes of infrared light - and wherever one needs to transmit data, there is always a protocol involved. The RC-5 protocol from Philips has been used in TVs, VCRs and other appliances since the past three decades. It was developed by Philips but was adopted by many other manufacturers. Now days RC-5 has been superseded by RC-6 and various other protocols from various other manufacturers. These newer protocols have better features and are more flexible. San Bergmans's KnowledgeBase on Consumer IR is a nice place to lookup information (protocol specs, circuits, embedded code) on any of the old or new IR based protocols. Here is how a RC-5 TV remote control transmitter unit looks like: And here is a InfraRed receiver/demodulator: A RC-5 codeword is 14 bit long. The first two are the start bits, then comes the toggle bit and finally the 5 bits ...

I²S stands for Inter Integrated Sound and is similar to the I²C which is used for transmitting data between Chips on a circuit board. ( wikipedia article on I²S). I²S is used for connecting digital audio devices together, (for example between the main processor and the audio codec chip on cell phones or computers or between the CD transport and the DAC in a CD player). I2S interface consists of at least 3 signals: Clock Left right clock Data line The eKA8562A Chip which is a USB Audio Controller (and can be used as an oscilloscope ) sports an I²S interface. Here are a few signals captured at the various pins (I²S output) on this chip: Pin 5 of eKA8562A - I²S BCLK Output Clock - This signal is used as the clock to latch in the bits appearing on the data line. Pin 6 of eKA8562A - I²S LRCLK Output Left Right Clock - This signal is used to tell the receiving devi...