A UART, SPI and I2C peripheral are all available on one part but share pins. The document to consult is
Answer: C
Headline peripheral counts are per-device totals and say nothing about which combinations can appear at the pins at once. The multiplexing table is where the conflict between the second SPI and the converter inputs becomes visible.
Please log in or register to report this question.
The termination resistors on a CAN bus are fitted
Answer: D
Two 120 ohm resistors, one at each physical extremity, match the cable and suppress reflections; fitting one at every node loads the bus until no transceiver can drive it. Stub lengths from the backbone to each node also have to be kept short.
Please log in or register to report this question.
A three-wire SPI variant dispenses with
Answer: A
Half duplex operation over a single data line saves a pin where the device never needs to send and receive at once. The clock, the select and the ground are all indispensable, and the clock in particular is what makes SPI synchronous.
Please log in or register to report this question.
A wireless link is chosen over a wired one for a sensor mainly when
Answer: B
Installation cost, moving parts and inaccessible locations are what justify the radio, since on every technical measure a wire is better. Wireless costs power, adds latency that is hard to bound and brings a whole class of interference problems with it.
Please log in or register to report this question.
Comparing a UART link with a CAN link for two boards a metre apart inside one enclosure, the UART is
Answer: C
Correct answer: adequate and much cheaper, needing no transceiver
Over a metre inside one enclosure a plain UART works directly between two microcontroller pins with no transceiver, no termination and no protocol controller. CAN’s differential signalling, arbitration and error handling exist for long, noisy, multi-node buses, and none of that is needed here. The UART does detect errors, through parity and framing, and a metre is far within its range.
Please log in or register to report this question.
