The analysis is as follows :
Question 1
APB1 is up to 36MHZ ,
APB2 is up to 72MHZ
, and the peripherals mounted on APB1 and APB2 (check the manual and remember it!)
Question 2
The STM32 chip integrates a 12-bit A/D converter, which is a successive approximation analog-to-digital converter . It has up to 18 channels and can measure 16 external and 2 internal sources. (Check the manual!)
Choose item D for question 3
The basic skills of this test to simplify the logic function
The formula A+BC=(A+B)(A+C) is the key! A lot of people forget this formula or don't use it flexibly.
Choose item A for question 4
The diode is a temperature-sensitive device. The influence of temperature change on its volt-ampere characteristics is mainly manifested in that
with the increase of temperature, its forward characteristic curve shifts to the left, that is, the forward voltage drop decreases ; the reverse characteristic curve moves down, That is, the reverse current increases .
The working mechanism of the semiconductor: the reverse saturation current is generated by the drift movement of the minority carriers in the diode. These minority carriers are generated due to the thermal excitation of the semiconductor to break away from the covalent bond. The more, the greater the saturation current.
Question 5 Choose ABC
Choose item D for question 6
When it comes to the three-stage pipeline, we must think of the execution process of the microcomputer ----> instruction fetching, decoding, execution, and so on.
The CM3 core uses a three-stage pipeline, and of course there are more complex multi-stage pipelines, but it is not that the more the instruction pipeline stages are, the better. The number of pipeline stages needs to be determined according to the specific requirements of the microprocessor.
Choose item A for question 7
The so-called 8421 code, the binary number represented by each "1" can be added up to get the decimal number it represents. From left to right, the weight of each "1" represents the numbers "8", "4", "2", and "1", hence the name 8421 code.
Taking the D flip-flop as an example, a flip-flop represents one status bit, and 4 status bits are required here.
Choose item C for question 8
Access to the collective circuit. The common collector circuit has the characteristics of voltage following, and the input resistance is large, which can amplify the current and power.
The common collector circuit is often called an emitter follower or an emitter follower. It introduces a voltage series negative feedback, the input resistance is large, and the output resistance is small. In fact, there are two common forms of common-collector amplifier circuits: common-collector basic amplifier circuits and fixed-bias common-collector amplifier circuits.
Derived from Networks:
The three basic amplification circuit analyses are divided into static analysis and dynamic analysis, also known as DC analysis and AC analysis. When there is no signal input, each current and voltage in the amplifier circuit is a constant DC quantity, which is called static state, and the analysis of static state is called static analysis;
When there is an AC signal input, the input AC signal will be superimposed on the DC amount for amplification and transmission in the amplifier circuit. At this time, the voltage and current in the circuit are in a state of change, which is called dynamic, and the analysis of dynamic is called dynamic analyze.
When performing static analysis, first draw the DC path of the amplifying circuit, and then find the static operating point by analytical or graphical method, that is, find IBQ, ICQ, UCEQ. The purpose of setting the static operating point is to prevent the signal from being amplified during the process. distortion occurs. When performing dynamic analysis, first draw the AC path of the amplifier circuit and the micro-change equivalent circuit, and then obtain the voltage amplification factor Au, the input resistance ri and the output resistance ro in the micro-change equivalent circuit of the amplifier circuit.
Choose item C for question 9
Be good at using " empty short" and "empty break" , just list equations to solve.
The two input terminals are approximately equipotential, which is equivalent to "short circuit"
. The differential mode input resistance of the op amp is very large, resulting in a very small input current, so it is equivalent to "open circuit"
Question 10 Choose ABD Item
It can be seen from the figure that the LSI (internal low-speed clock) is not the clock source that drives the system clock SYSCLK.