Topic: Communication Systems
A UART is configured to transmit 8 bit data, 1 start bit and 1 stop bit. The serial data output is observed on oscilloscope, which looks like a square wave with frequency of 9600 Hz. What is the baud rate transmitted data?
- A. Baud rate = 9600, Data=55h
- B. Baud rate = 19200, Data=FFh
- C. Baud rate = 19200, Data=55h
- D. Baud rate = 9600, Data=AAh
Answer: B. Baud rate = 19200, Data=FFh
Explanation: Baud rate is defined as the number of symbols or pulses per second. If the serial data output looks like a square wave with a frequency of $9600 \text{ Hz}$, one full cycle of the square wave contains two symbols (one high, one low). Therefore, the Baud rate is $2 \times 9600 = 19200$. (Note: The official key selects (b), indicating Data=FFh, though standard derivations often point to alternating bits like 55H producing a continuous square wave. The provided answer reflects the official document).