MECHATRONICS UPDATED EXAMS CORRECT
QUESTIONS AND ANSWERS SURE A+
✔✔Serial Peripheral Interface (SPI) - ✔✔- One of the ways digital information can be
sent back and forth between integrated circuit (IC) chips
- "Synchronous" Serial. It doesn't need to be precise and is incredibly simple to
implement. It's also very fast and very inexpensive
- When waking up the peripheral device, SPI has a chip select pin dedicated to
controlling each peripheral device. This is an inverted logic pin, so whenever the
controller wants to wake up the peripheral device, it sets the device's chip select pin to
be low and then sends or receives data to or from it.
- Private road, only one car on it
✔✔I2C - ✔✔- For I2C, there are only ever two pins, a clock and a data pin. Each
peripheral device has a predetermined address such that when the controller wants to
"talk" to a particular device, it begins by "shouting" the name across the bus. That
device then acknowledges by sending an ACK bit back to the controller to let it know
that it's listening.
- Like calling for a car on a busy highway
✔✔Asynchronous Serial - ✔✔- 8-N-1 is the most common protocol used for Universal
Asynchronous Receive Transmit (UART)
-UART doesn't use a shared clock wire. Instead, sender and receiver agree on a
specific Baud Rate beforehand and "hope" their internal timers stay in sync long enough
to transmit a few bits. Only requires TX (transmit) and RX (receive) wires
- Because there is no clock wire to tell the receiver exactly when to "read" a bit, UART
uses a Start Bit. When the sender wants to talk, it pulls the line that sits normally high to
low for one bit-period. This wakes the receiver up to start its internal timer
- 8 refers to the amount of data bits. This is the payload. After the start bit, the 8 bits
sent are the actual data
- N refers to no parity, N means we aren't using the error checking bit.
- 1 refers to the stop bit. After the data bits, the sender pulls the line High for at least
one bit-period. This signals the end of the byte and resets the idle state so it's ready for
the next start bit (pulls back to high)
, ✔✔Parallel Interface - ✔✔- sends multiple bits of data simultaneously over multiple
wires. It's like a 8-lane highway compared to a single-lane road. An entire byte (8 bits) is
delivered in a single "clock tick"
- it has a high initial speed and simple logic. It's also very inexpensive with a
variable/arbitrary message size. However, the pin use is terrible and requires a separate
pin for each bit (typically at least 8), and usually has no acknowledgement.
✔✔Analog-to-Digital Conversion (ADC) - ✔✔- Real world data into a computer
✔✔Dual Slope ADC - ✔✔- Dual Slope technique employs an op amp wired as an
integrator (w/ a capacitor in its negative feedback loop). It achieves high resolution but
is very slow
✔✔Delta Sigma ADC - ✔✔- Delta sigma uses oversampling to achieve high resolution
and conversion rates
✔✔Flash ADC - ✔✔- Flash ADC is the fastest but most expensive. Uses a comparator
circuit (basically an op amp) for every possible output value
✔✔Successive approximation register (SAR) ADC - ✔✔- Successive approximation
register ADC uses digital to analog convertor to find reference voltage, then compare
unknown analog input voltage to this voltage. It then sees if value is above or below,
and cuts the comparing set in half
✔✔Nyquist-Shannon Theorem - ✔✔- Nyquist-Shannon sampling theorem basically
states that you need to capture at least two samples of an input signal within its period
in order to be able to accurately determine its original frequency. This means that the
sampling frequency must be at least twice the highest frequency that you are interested
in measuring. fbeat=|f1-f2|
-The Nyquist frequency is defined as exactly half of a system's sampling rate.
✔✔ Ohms Law - ✔✔- V=IR
- the relationship between voltage, current, and resistance
✔✔Power Law - ✔✔- P=IV
- The relationship between voltage, power, and current
✔✔Voltage Divider Circuit - ✔✔Vout = Vin*(R2)/(R1+R2)
- Most important Equation in all of mechatronics
- Scales down a higher voltage so that it can be worked with throughout a circuit
- Can also be read by a DMM
✔✔Potentiometers (how they work) - ✔✔- Variable resistors that can be used as a
voltage divider
QUESTIONS AND ANSWERS SURE A+
✔✔Serial Peripheral Interface (SPI) - ✔✔- One of the ways digital information can be
sent back and forth between integrated circuit (IC) chips
- "Synchronous" Serial. It doesn't need to be precise and is incredibly simple to
implement. It's also very fast and very inexpensive
- When waking up the peripheral device, SPI has a chip select pin dedicated to
controlling each peripheral device. This is an inverted logic pin, so whenever the
controller wants to wake up the peripheral device, it sets the device's chip select pin to
be low and then sends or receives data to or from it.
- Private road, only one car on it
✔✔I2C - ✔✔- For I2C, there are only ever two pins, a clock and a data pin. Each
peripheral device has a predetermined address such that when the controller wants to
"talk" to a particular device, it begins by "shouting" the name across the bus. That
device then acknowledges by sending an ACK bit back to the controller to let it know
that it's listening.
- Like calling for a car on a busy highway
✔✔Asynchronous Serial - ✔✔- 8-N-1 is the most common protocol used for Universal
Asynchronous Receive Transmit (UART)
-UART doesn't use a shared clock wire. Instead, sender and receiver agree on a
specific Baud Rate beforehand and "hope" their internal timers stay in sync long enough
to transmit a few bits. Only requires TX (transmit) and RX (receive) wires
- Because there is no clock wire to tell the receiver exactly when to "read" a bit, UART
uses a Start Bit. When the sender wants to talk, it pulls the line that sits normally high to
low for one bit-period. This wakes the receiver up to start its internal timer
- 8 refers to the amount of data bits. This is the payload. After the start bit, the 8 bits
sent are the actual data
- N refers to no parity, N means we aren't using the error checking bit.
- 1 refers to the stop bit. After the data bits, the sender pulls the line High for at least
one bit-period. This signals the end of the byte and resets the idle state so it's ready for
the next start bit (pulls back to high)
, ✔✔Parallel Interface - ✔✔- sends multiple bits of data simultaneously over multiple
wires. It's like a 8-lane highway compared to a single-lane road. An entire byte (8 bits) is
delivered in a single "clock tick"
- it has a high initial speed and simple logic. It's also very inexpensive with a
variable/arbitrary message size. However, the pin use is terrible and requires a separate
pin for each bit (typically at least 8), and usually has no acknowledgement.
✔✔Analog-to-Digital Conversion (ADC) - ✔✔- Real world data into a computer
✔✔Dual Slope ADC - ✔✔- Dual Slope technique employs an op amp wired as an
integrator (w/ a capacitor in its negative feedback loop). It achieves high resolution but
is very slow
✔✔Delta Sigma ADC - ✔✔- Delta sigma uses oversampling to achieve high resolution
and conversion rates
✔✔Flash ADC - ✔✔- Flash ADC is the fastest but most expensive. Uses a comparator
circuit (basically an op amp) for every possible output value
✔✔Successive approximation register (SAR) ADC - ✔✔- Successive approximation
register ADC uses digital to analog convertor to find reference voltage, then compare
unknown analog input voltage to this voltage. It then sees if value is above or below,
and cuts the comparing set in half
✔✔Nyquist-Shannon Theorem - ✔✔- Nyquist-Shannon sampling theorem basically
states that you need to capture at least two samples of an input signal within its period
in order to be able to accurately determine its original frequency. This means that the
sampling frequency must be at least twice the highest frequency that you are interested
in measuring. fbeat=|f1-f2|
-The Nyquist frequency is defined as exactly half of a system's sampling rate.
✔✔ Ohms Law - ✔✔- V=IR
- the relationship between voltage, current, and resistance
✔✔Power Law - ✔✔- P=IV
- The relationship between voltage, power, and current
✔✔Voltage Divider Circuit - ✔✔Vout = Vin*(R2)/(R1+R2)
- Most important Equation in all of mechatronics
- Scales down a higher voltage so that it can be worked with throughout a circuit
- Can also be read by a DMM
✔✔Potentiometers (how they work) - ✔✔- Variable resistors that can be used as a
voltage divider
