Chapter Questions
True or false. The output of most sensors is analog.
True or false. A 10-bit ADC has 10-bit digital output.
True or false. $A D C 0848$ is an 8-bit $A D C$.
True or false. MAX1112 is a 10-bit ADC.
True or false. An ADC with 8 channels of analog input must have 8 pins, one for each analog input.
True or false. For a serial $A D C$, it takes a longer time to get the converted digital data out of the chip.
True or false. ADC0848 has 4 channels of analog input.
True or false. MAX 1112 has 8 channels of analog input.
True or false. ADC0848 is a serial ADC.
True or false. MAX 1112 is a parallel ADC.
Which of the following ADC sizes provides the best resolution?$\begin{array}{lllll}\text { (a) 8-bit } & \text { (b) 10-bit } & \text { (c) 12-bit } & \text { (d) 16-bit } & \text { (e) They are all the same. }\end{array}$
In Question 11, which provides the smallest step size?
Calculate the step size for the following $\mathrm{ADCs}$, if $\mathrm{V}_{\text {ref }}$ is $5 \mathrm{~V}$ :(a) 8-bit(b) 10-bit (c) 12-bit(d) 16-bit
With $\mathrm{V}_{\text {ref }}=1.28 \mathrm{~V}$, find the $\mathrm{V}_{\text {in }}$ for the following outputs:(a) D7-D0 = 11111111(b) D7-D0 $=10011001$(c) D7-D0 $=1101100$
In the $\mathrm{ADC} 0848$, what should the $\mathrm{V}_{\text {ref }}$ value be if we want a step size of $5 \mathrm{mV}$ ?
With $\mathrm{V}_{\mathrm{ref}}=2.56 \mathrm{~V}$, find the $\mathrm{V}_{\text {in }}$ for the following outputs:(a) $\mathrm{D} 7-\mathrm{D} 0=11111111$(b) D7-D0 $=10011001$(c) D7-D0 $=01101100$
True or false. The ATmega32 has an on-chip A/D converter.
True or false. A/D of the ATmega32 is an 8-bit ADC.
True or false. ATmega32 has 8 channels of analog input.
True or false. The unused analog pins of the ATmega32 can be used for $\mathrm{I} / \mathrm{O}$ pins.
True or false. The A/D conversion speed in the ATmega32 depends on the crystal frequency.
True or false. Upon power-on reset, the A/D module of the ATmega32 is turned on and ready to go.
True or false. The A/D module of the ATmega32 has an external pin for the start-conversion signal.
True or false. The A/D module of the ATmega32 can convert only one channel at a time.
True or false. The A/D module of the ATmega32 can have multiple external $\mathrm{V}_{\text {ref }}{ }^{+}$at any given time.
True or false. The A/D module of the ATmega32 can use the $V_{c c}$ for $V_{\text {ref }}$.
In the A/D of ATmega32, what happens to the converted analog data? How do we know that the $\mathrm{ADC}$ is ready to provide us the data?
In the A/D of ATmega32, what happens to the old data if we start conversion again before we pick up the last data?
For the A/D of ATmega32, find the step size for each of the following $V_{\text {ref }}$ :(a) $\mathrm{V}_{\text {ref }}=1.024 \mathrm{~V}$(b) $\mathrm{V}_{\text {ref }}=2.048 \mathrm{~V}$(c) $\mathrm{V}_{\text {ref }}=2.56 \mathrm{~V}$
In the ATmega32, what should the $V_{\text {ref }}$ value be if we want a step size of 2 $\mathrm{mV}$ ?
In the ATmega32, what should the $V_{\text {ref }}$ value be if we want a step size of 3 $\mathrm{mV}$ ?
With a step size of $1 \mathrm{mV}$, what is the analog input voltage if all outputs are 1 ?
With $\mathrm{V}_{\text {ref }}=1.024 \mathrm{~V}$, find the $\mathrm{V}_{\text {in }}$ for the following outputs:(a) D9-D0 $=0011111111$ (b) D9-D0 $=0010011000$ (c) D9-D0 $=0011010000$
In the $\mathrm{A} / \mathrm{D}$ of ATmega32, what should the $\mathrm{V}_{\text {ref }}$ value be if we want a step size of $4 \mathrm{mV}$ ?
With $\mathrm{V}_{\text {ref }}=2.56 \mathrm{~V}$, find the $\mathrm{V}_{\text {in }}$ for the following outputs:(a) D9-D0 = 1111111111 (b) D9-D0 $=1000000001$ (c) D9-D0 $=1100110000$
Find the first conversion times for the following cases if $\mathrm{XTAL}=8 \mathrm{MHz}$. Are they acceptable?(a) Fosc/2$\begin{array}{ll}\text { (b) Fosc/4 } & \text { (c) Fosc/8 }\end{array}$(d) Fosc/16(e) Fosc/32
Find the first conversion times for the following cases if $\mathrm{XTAL}=4 \mathrm{MHz}$. Are they acceptable?(a) Fosc/8(b) Fosc $/ 16$(c) $\operatorname{Fosc} / 32$(d) Fosc/64
How do we start conversion in the ATmega32?
How do we recognize the end of conversion in the ATmega32?
Which bits of which register of the ATmega32 are used to select the A/D's conversion speed?
Which bits of which register of the ATmega32 are used to select the analog channel to be converted?
Give the names of the interrupt flags for the A/D of the ATmega32. State to which register they belong.
Upon power-on reset, the $\mathrm{A} / \mathrm{D}$ of the ATmega32 is given (on, off).
What does it mean when a given sensor is said to have a linear output?
The LM34 sensor produces $\mathrm{mV}$ for each degree of temperature.
What is signal conditioning?
True or false. DAC0808 is the same as DAC1408.
Find the number of discrete voltages provided by the $n$-bit DAC for the following:(a) $n=8$ (b) $n=10$ (c) $n=12$
For DAC1408, if $\mathrm{I}_{\mathrm{ref}}=2 \mathrm{~mA}$, show how to get the $\mathrm{I}_{\mathrm{out}}$ of $1.99$ when all inputs are HIGH.
Find the $\mathrm{I}_{\mathrm{out}}$ for the following inputs. Assume $\mathrm{I}_{\mathrm{ref}}=2 \mathrm{~mA}$ for DAC0808.(a) 10011001(b) 11001100(c) 11101110(d) 00100010(e) 00001001(f) 10001000
To get a smaller step, we need a DAC with (more, fewer) digital inputs.
To get full-scale output, what should be the inputs for DAC?