By Sascha Wagner
As you’ve probably experienced, having very flexible hardware is critical in automotive designs because the protocols used in the industry are not standardized. Every OEM can define and use its own message structures and properties. Signal properties can be RF frequency, data rate, coding, modulation or deviation. Any combination, such as a short preamble or wake-up pattern (WUP) followed by a big gap with a start frame identifier (SFID) and a special ID at the beginning of the payload, can be used. Signal properties can also be mixed within one message. One device that can help you adapt to multiple automotive protocols is the Atmel® ATA583x family of highly integrated transceiver ICs. These devices include an AVR® core, an RX digital signal processor (DSP) and a separate analog front end with two separate receive paths that allow two signals to be searched in parallel. These new transceivers cover most known protocols without limitations, as well as the standard frequencies.
A unique feature of the devices is their ability to handle mixed modulation within one message. Mixed modulation involves the use of two reception paths for the transceiver: one path for the wake condition and one for synchronization and reception. This simple feature allows the devices to handle complex protocols, and by using mixed modulation plus the gaps between the WUP and SFID, output power, and thus the transmission range, can be increased.
For diagrams and more details about how you can increase car access system flexibility with the ATA583x transceiver family, read the full article, “Highly Integrated AVR MCU-Based UHF Transceiver Family Increases Car Access System Flexibility.”