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ECEN 1060 Final

Terms in this set (95)

Which Timers are 8 bit?
Timer0 & Timer2
Which Timer(s) are 16 bit?
Timer1
What are the TCCRxA:B Registers for?
Controlling the timers.
What register and what bits do you write to to start Timer0 and set the Prescaler.
TCCR0B, CS00:02
What three flags are present in the TIFR register?
OCFxA:B, TOVx
True or False: The following AVR instruction is legal.

LDI R20, 500
False
True or False: The following AVR instruction is legal.

ADD R20, R11
True
True or False: The following AVR instruction is legal.

ADD R32, R16
False
True or False: The following AVR instruction is legal.

LDI R1, 0
False
True or False: The following AVR instruction is legal.

STS OCR0, R23
True
What are the two advantages of RJMP over JMP?
Uses less memory space.
Faster
True or False: Harvard Architecture uses the same address and data busses to fetch both code and data.
False
True or False: A microcontroller has a fixed amount of RAM on the chip.
True
True or False: The AVR I/O registers are only used for storing data.
False
True or False: Every Member of the AVR family wakes up to address 0x0000.
True
True or False: We cannot load immediate values into the AVR internal RAM directly.
True
The instruction "BRNE BACK" makes its decision based on what flag in SREG?
Zero Flag
True or False: Control can be transferred anywhere within the 4M of the AVR's code space by using the CALL instruction.
True
To what are the AVR's I/O ports configured to upon reset?
Input
True or False: Control can be transferred anywhere within the 4M of the AVR's code space by using the RCALL instruction.
False
True or False: In the AVR, the instruction fetching and execution are done at the same time.
True
What is the oscillator frequency is the machine cycle = 100nsec?
10 MHz
What is the machine cycle time if the crystal frequency is 8 MHz?
125 nsec
Is the following instruction valid or invalid?

CLH
Valid
Is the following instruction valid or invalid?

CBI PORTC.3
Invalid
Is the following instruction valid or invalid?

SBR SREG, 1
Invalid
Is the following instruction valid or invalid?

BST R20, 3
Valid
Is the following instruction valid or invalid?

BLD PORTD, 0
Invalid
What are the three parts of a macro?
.MACRO
body of macro
.ENDMACRO
True or false: TCCR0B is a bit-addressable register.
False
True or false: The AVR EEPROM memory is used for both program code and data.
False
True or false: TIFR0 is a bit-addressable register.
False
True or false: The ATmega328P has 1024 bytes of EEPROM memory.
True
True or false: In the AVR, EPROM memory is read and write memory.
True
When using ATmega328P code space for data, the total size of an array must not exceed 256 bytes.
False
What are the three EEPROM registers?
EEDR
EEARH:L
EECR
What are the four bits of EECR and what do they do when set?
EERE: Causes a read operation if EEPE is zero.
EEPE: Starts a write operation if EEMPE was set within 4 clock cycles.
EEMPE: Allows writing to EEPROM
EERIE: Enables the EEPROM Ready Interrupt
What are the 5 steps to write to EEPROM?
1. Wait until EEPE becomes zero.
2. Write new EEPROM address to EEAR (Optional)
3. Write new EEPROM data to EEDR (Optional)
4. Set the EEMPE bit to 1 (in EECR register)
5. Within 4 clock cycles after setting EEMPE, set EEPE to 1.
What are the 4 steps to read from EEPROM?
1. Wait until EEPE becomes 0.
2. Write new EEPROM address to EEAR (Optional)
3. Sett the EERE bit to 1
4. Read EEPROM data from EEDR
What is the maximum number of parameters a macro can take?
10
When the CSx2:x0 bits in TCCRx are loaded with 6 or 7, how does this affect the timer?
The timer will count up based on external clock pulses from pins Tx where 'x' is the same x (0 or 1) in CSx2:x0.
Where are the pins for INT0 and INT1 located?
PORTD.2 and PORTD.3
What are the 3 interrupt enable bits in each of the timer interrupt registers?
OCIExB (Output Compare Interrupt Enable B)
OCIExA (Output Compare Interrupt Enable A)
TOIEx (Timer Overflow Interrupt Enable)
Which registers are the timer interrupt enable bits located?
TIMSK0:2
What register contains the two external interrupt enable bits?
EIMSK (External Interrupt Mask)
How are the external interrupts triggered by default?
Low-Level-Triggered
Which register do you use to change how the external interrupts are triggered?
EICRA (External Interrupt Control Register A)
When setting EICRA, what is the trigger result of the following?
ISCx1 ISCx0
0 0 = ???
0 1 = ???
1 0 = ???
1 1 = ???
Low-Level
Any Change
Falling-Edge
Rising Edge
If the EINT0 and EINT1 interrupts trigger at the same time, which will be serviced first? Be specific.
EINT0
If the TOV0 and TOV1 interrupts trigger at the same time, which will be serviced first? Be specific.
TOV1
What are the 0 and 1 TTL voltage levels?
0 = 0V to 0.8V
1 = 2V to 5V
What are the 0 and 1 RS232 voltage levels?
0 = +3V to +25V
1 = -3V to -25V
Placing a serial character between a start and stop bit is called...
Framing
In serial communication, the start bit is always a...
0
In serial communication, a 0 is referred to as a ________ and a 1 is a ________.
Space. Mark.
What is the difference between the MAX232 and MAX233
The MAX 233 uses on-chip capacitors.
What register is used to set the baud rate in serial communication?
UBRR
Assuming XTAL = 16MHz, what value do we load into the UBRR register to set the baud rate to 9600?
0x67 (HEX) or 103 (DEC)
Assuming XTAL = 16MHz, what value do we load into the UBRR register to set the baud rate to 38400?
0x19 (HEX) or 25 (DEC)
What is the formula to find your desired baud rate?
Fosc / (16( UBRR + 1 ))
Read the LOW ________, write the low ________.
Read the LOW first, write the low last.
What is the formula to find the value you load into the UBRR register for a desired baud rate?
(Fosc / 16( Desired Baud Rate ) ) - 1
True or False: The UDR register(s) on the ATmega328P is two registers.
True
Which register contains the flags used in serial communication?
UCSR0A
What does the RXC0 flag do?
This flag is set when there is new data in the receive buffer that has not yet been read.
What does the TXC0 flag do?
This flag is set when the entire frame in the transmit shift register has been transmitted and there is no new data available.
What does the UDRE0 flag do?
This flag is set when the transmit data buffer is empty and ready to receive new data.
Which register contains the enable bits for the USART interrupts?
UCSR0B
What does the RXCIE0 bit in UCSR0B do?
Enables the USART Receive Complete Interrupt.
What does the TXCIE0 bit in UCSR0B do?
Enables the USART Transmit Complete Interrupt.
Which register sets the parity, stop bit, Character Size, and mode of the AVR USART?
UCSR0C
Which bits in UCSR0C are used to set the USART character size, and what do you load them with for a character size of 8?
UCSZ01:00. 11 (BIN) or 3 (DEC)
What are the 5 steps to transmit a character using the AVR's USART, 8 bit character size, one stop bit, no parity?
1. Set the TXEN0 bit of UCSR0B.
2. Set the UCSZ00 and UCSZ01 bits of UCSR0C (character size = 8).
3. Load UBRR0 with baud rate calculation
4. Load UDR0 with the character to transmit.
5. Monitor the UDRE0 bit of UCSR0A to make sure UDR0 is ready for the next byte.
What are the 5 steps to receive a character using the AVR's USART, 8 bit character size, one stop bit, no parity?
1. Set the RXEN0 bit of UCSR0B.
2. Set the UCSZ00 and UCSZ01 bits of UCSR0C (character size = 8).
3. Load UBRR0 with baud rate calculation
4. Monitor the RXC0 bit of UCSR0A to see if an entire byte has been received.
5. When RXC0 is high, move the contents of UDR0 somewhere else.
What is the formula to calculate the error for a baud rate?
(Calculated Baud Rate - Desired Baud Rate) / Desired Baud Rate
What are the 14 pins of a standard LCD screen? (Hint: 8 of them have a VERY similar function!)
VSS (Ground)
VCC (+5V Power Supply)
VEE (Contrast Control)
RS (0 = Command, 1 = Data)
R/W (0 = Write, 1 = Read)
E (Enable)
DB0:7 (8-bit Data Bus)
What is the formula to calculate the step size of an ADC?
VREF / numofSteps
What is the formula for the data output of an ADC?
VIN / stepSize
How many steps does an 8-bit ADC have?
256
How many steps does a 10-bit ADC have?
1024
True or false: The AVR ADC is 8-bit.
False! It's 10-bit.
How many analog inputs does the ATmega328P contain?
6
Which registers contains the ADC output data?
ADCH:L
What three options are available for the ADC's VREF?
1. AVCC
2. Internal 1.1V reference
3. External AREF pin
What is the maximum clock input frequency for the AVR's ADC?
200kHz
What are the six major registers associated with the AVR's ADC?
1. ADCH (High data)
2. ADCL (Low data)
3. ADCSRA (ADC Control and Status Register A)
4. ADCSRB (ADC Control and Status Register B)
5. ADMUX (ADC Multiplexer Selection Register)
6. DIDR (Digital Input Disable Register)
What do the REFS1:0 bits of the ADMUX register do?
Select the reference voltage for the ADC.
What does each value (00 to 11) of REFS0:1 in ADMUX select?
00 = AREF pin
01 = AVCC
10 = Reserved
11 = Internal 1.1V
What happens when the ADLAR bit of ADMUX is set to 1?
The output ADC data in ADCH:L becomes left justified.
What does the ADEN bit of ADCSRA do?
Enables the ADC.
What does setting the ADSC bit of ADCSRA to 1 do?
Starts the conversion of an analog voltage to digital signals.
What does the ADATE bit of ADCSRA do?
Enables the auto trigger mode of the ADC.
Which bits in ADCSRA are the ADC interrupt flag, and ADC interrupt enable?
ADIF (ADC Interrupt Flag)
ADIE (ADC Interrupt Enable)
What are the steps to program the AVRs ADC?
1. Make the pin for the selected ADC channel an input pin.

2. Turn on the ADC module of the AVR because it is disabled upon power-on to save power.

3. Select the conversion speed. We use registers ADPS2:0 to select the conversion speed.

4. Select voltage reference and ADC input channels. We use the REFS0 and the REFS1 bits in the ADMUX register to select voltage reference and the MUX3:0 bits in ADMUX to select the ADC input channel.

5. Activate the start conversion bit by writing a 1 to the ADSC bit of ADCSRA.

6. Wait for the conversion to be completed by polling the ADIF bit in the ADCSRA register.

7. After the ADIF bit has gone HIGH, read the ADCL ADCH registers to get the digital data output. Notice that you have to read ADCL before ADCH; otherwise the result will not be valid.
What do the ADPS2:0 bits of ADCSRA do?
Set the ADC conversion speed.
Verified questions
chemistry
absorbs 125 Jof heat and does $687 \mathrm{~J}$
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health
How might a person's ability to speak be affected by a stroke that damages the left hemisphere of the brain?
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health
Write in standard notation: $1.0\times 10^4$
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chemistry
One way to estimate the effective charge $(Z_\text {eff})$ of a many-electron atom is to use the equation $I_1 = (1312 \mathrm{~kJ} / \mathrm{mol})\left(Z_{\mathrm{eff}}^2 / n^2\right)$, where $I_1$ is the first ionization energy and $n$ is the principal quantum number of the shell in which the electron resides. Use this equation to calculate the effective charges of $\mathrm{Li}, \mathrm{Na}$, and $\mathrm{K}$. Also calculate $Z_{\text {eff }} / n$ for each metal. Comment on your results.
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