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WorksheetsT7_T11
Total questions: 20
Worksheet time: 10mins
Name
Class
Date
1.
A DAC0808 circuit produces a distorted sine wave when fed from PIC. What is the most probable software-level cause?
a)
Incorrect reference voltage
b)
Lookup table values not properly sequenced
c)
DAC input pins shorted
d)
Missing analog filter
2.
In embedded waveform generation using DAC, which C programming strategy ensures continuous waveform output without delay blocking?
a)
Using nested loops for timing
b)
Using timer interrupt-based update of DAC data
c)
Using ADC interrupt
d)
Using NOP delays between writes
3.
A student connects LEDs directly to PORTC pins without resistors. What is the most likely outcome?
a)
Brighter LED output
b)
Possible port damage due to overcurrent
c)
Automatic current limiting
d)
Faster blinking rate
4.
In designing a simple home protection system using embedded C, which function of PIR sensor output is typically used in the code?
a)
It acts as an analog feedback to PWM
b)
It generates an external interrupt signal
c)
It enables UART communication
d)
It resets watchdog timer
5.
While designing an embedded LED display board using PIC18F4520, TRISB is configured as 0x00. What is the effect of this setting on LED control?
a)
All LEDs connected to Port B can now be driven as outputs
b)
All LEDs connected to Port B are disabled
c)
All Port B pins act as inputs for the LED
d)
Port B becomes analog input-only
6.
An engineer connects a 4-bit LCD to PORTD of a PIC and notices garbled characters on display. Which of the following is the most likely cause?
a)
Incorrect TRISD configuration
b)
LCD not initialized in correct mode (0x28)
c)
Wrong data delay between nibbles
d)
All of the above
7.
When interfacing a keypad to PORTB, why is configuring internal pull-ups critical?
a)
To prevent false key detections due to floating inputs
b)
To increase debounce speed
c)
To enable analog readings from keys
d)
To make keys more sensitive
8.
A motion detector using PIR sensor connected to RA1 continuously triggers even when no motion occurs. Which fix is most effective?
a)
Enable RA1 as analog input
b)
Configure RA1 as digital input and stabilize power lines
c)
Reduce PIR voltage supply
d)
Disable ADC module
9.
In a home automation project, a buzzer connected to RC2 fails to turn OFF after trigger. Which embedded C technique helps prevent this issue?
a)
Polling loops for each condition
b)
Timer interrupt–based control logic
c)
Direct port toggling without delay
d)
Nested delay loops
10.
While debugging a PIC test board, no digital outputs are observed. Oscillator settings are correct. What should be verified next?
a)
Check configuration of LAT vs PORT registers
b)
Verify that all TRIS bits are cleared for output ports
c)
Inspect EEPROM configuration
d)
Run ADC calibration
11.
During I2C transfer, what ensures bus arbitration when multiple masters initiate communication simultaneously?
a)
Clock stretching
b)
Address matching
c)
Open-drain configuration with SDA monitoring
d)
Hardware priority encoder
12.
In a traffic light controller coded in embedded C, why are timers preferred over delay loops?
a)
They allow concurrent handling of other tasks
b)
They make code simpler to debug
c)
They generate variable voltage signals
d)
They reduce RAM usage
13.
While designing serial communication between PIC and PC, why must ground be common?
a)
To ensure common reference voltage for signal levels
b)
To reduce noise
c)
To prevent data reflection
d)
To enable full duplex
14.
An RTC DS1307 outputs incorrect time after reset. Which step is essential after power-up?
a)
Enable oscillator bit in seconds register
b)
Reinitialize I2C bus speed
c)
Send STOP condition before first write
d)
Reset EEPROM
15.
An embedded system uses RS232 communication between PIC18F4520 and PC. Why is a MAX232 IC required?
a)
To convert voltage levels between TTL and RS232 standards
b)
To increase baud rate
c)
To provide parity checking
d)
To isolate grounds
16.
In RS485 network communication with multiple nodes, how is data collision avoided?
a)
Using differential line drivers
b)
Using half-duplex master-slave communication protocol
c)
By disabling interrupts
d)
By lowering baud rate
17.
While debugging I2C communication with DS1307, the master sends no ACK. What does it indicate?
a)
RTC not powered or missing pull-ups on SDA/SCL
b)
Bus speed too high
c)
Incorrect baud rate setting
d)
Incorrect TRIS configuration
18.
A designer connects an EEPROM using SPI. Data written is corrupted after power-up. What could be missing?
a)
EEPROM write enable latch command before write
b)
Proper clock phase selection
c)
Correct SPI mode
d)
High chip select timing
19.
The MSSP module in SPI mode transfers data via:
a)
Single-wire half-duplex method
b)
Two-wire full-duplex with MOSI and MISO
c)
Synchronous serial with clock only
d)
Asynchronous single line
20.
USART baud rate is doubled without changing oscillator frequency. Which setting caused it?
a)
BRGH = 1 in TXSTA register
b)
SYNC = 1 in RCSTA register
c)
SPEN = 0 in RCSTA register
d)
TXEN = 0 in TXSTA register
Reset
