NXP Microcontrollers Flashcards
What does the F in the name of an NXP microcontroller mean?
> It means that the microcontroller has an FPU.
This is a floating point unit which specialises in floating point calculations.
It allows floating point calculations to be done in a single clock cycle
What is a DSP?
This is a digital signal processor. This is good for audio applcations.
What is the dominant technology used in digital electronics?
CMOS
What is the arrangement for a CMOS NAND gate?
[Picture1]
What is the equation for switching energy? Why?
Capacitances within lines need to be discharged.
Equation: E = 1/2 × C × V^2
What is short-circuit power?
During switching there is a brief point where both n-type and p-type FETs are conducting at the same time and this causes a small short circuit.
How much power is lost during a short circuit situation for a NAND gate?
Only a very small amount of the overall switching power
What is leakage current?
This is the small current flow through transstors when they are off due to imperfections
What can leakage current do?
Drain batteries slowly over time
What is the equation for CMOS circuit power?
P = 0.5 × f × Vdd^2 × ∑[g ∈ c] Ag × Cg
f = freq Ag = Activity factor (how often it switches) Cg = Gate capacitance
What are 4 factors of reducing power consumption?
> Minimise the frequency
Minimise the number of gates
Minimise the activity (halt/power down any features that are not being used)
Minimise the voltage supply
What is an ARM Coretex-M Microcontroller that is an FPGA?
Coretex-M1
What is the difference between: > Coretex-M1 >Coretex-M0 >Coretex-M0+ > Coretex-M3 > Coretex-M4
> Coretex-M1 = FPGA >Coretex-M0 = MCU (low cost) >Coretex-M0+ = MCU (low-med cost) > Coretex-M3 = MCU (med-high cost) > Coretex-M4 = MCU (High cost)
What is the benefit of this CMOS NAND gate?
There isn’t a static current path from Vdd to Vss so static power consumption is low
