Is there a simple and practical way to boost the IO port of the MCU?

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WeChat *** does not have such a function, in order to get such a prompt function, can only be opened by the mobile company corresponding to the ** card call reminder business, how to open each mobile company is different, the reminder method is not the same, so if you want to know how to open and use, you can only go to the company corresponding to your ** card to open. WeChat *** does not have such a function, in order to get such a prompt function, can only be opened by the mobile company corresponding to the ** card call reminder business, how to open each mobile company is different, the reminder method is not the same, so if you want to know how to open and use, you can only go to the company corresponding to your ** card to open. WeChat *** does not have such a function, in order to get such a prompt function, you can only open the call reminder service by the mobile company corresponding to the ** card, how to open each mobile company is different, so if you want to know how to open and use, you can only go to the company corresponding to your ** card to open.

1. First of all, pay attention to the operation of 51 microcontroller when BAI is on the DU power, and do not execute the DAO line microcontroller back to the internal program when reset, and after reset, all IO ports of the 51 microcontroller are high;

2. Execute the program in the main function after the single-chip microcomputer reset, if you want to initialize the IO port to a low level, you need to set the IO low above the while loop; For example:

The general program is structured like this:

void main()

3. Based on the above principle, when designing the peripheral circuit of the single-chip microcomputer, in order to prevent the peripheral circuit from malfunctioning, the peripheral circuit is generally set to the low level of the IO port of the single-chip microcomputer

The IO of 51 is very special in that it belongs to SFR and cannot be addressed directly or indirectly, so it cannot be reversed arbitrarily like registers. Either modify it when defined, or use an interface function to realize the exchange of io in the interface function, this function can accept parameters or something, and it can be done more user-friendly.

Hardware can also be changed.

It is possible to transform it with software.

The landlord should explain what language to use.

It's just to redefine the port, what's the problem.

You see, when i=0, the binary is 00000000, so the corresponding colored lights are low, all bright, when the binary is 00000001, the last digit is 1, so the corresponding light is not on, the rest is bright, when the binary is 00000010, the penultimate digit is 1, the corresponding light is not on, and the rest is bright When i is 254, the binary is 11111110, and only the last digit is 0, so there is only one light on, At 255 hours, the binary 11111111 are all high level 1, and the lights are not on! In addition, let me tell you, one end of the lamp is fixed with a high level, so we need to be programmed to low level at the other end in order to be the lamp conduction and emitting light, here is to use the P0 port control.

The io port you say can only be 0 or 1 refers to a certain bit of the io port, for example, each p port has 8 bits.

The io port can only be given to 0 or 1, and it can't be given to other things, and there is no way to give it. What value you assign to an io port depends on what you want to do with this port. At the beginning of the program, the IO port should be initialized, for example, the LED that cannot light up a certain port, or the relay that cannot drive a certain port, or the thyristor that does not drive a certain port, etc.

After the program runs to a certain condition, such as a key is pressed, a certain load is working, and a certain condition is met, then change the state of a certain IO port. It's up to you to decide how your program flows.

The io port can only be zero and one. But the data expression doesn't have to be binary, and the I-o port doesn't have to work together at the same time... It doesn't seem like there's a requirement for assignment, but there are requirements for pins (circuits).。。。

P0 means p00 P07 i's range is 0 255, corresponding to your conversion to binary numbers is 0 11111111, when i=0, the state of P0 port is 00000000

There are four main methods of iO extension:

1) The method of parallel bus expansion.

2) Serial port expansion method.

3) IO port analog serial method.

4) Through the expansion method of IO in the microcontroller.

The C8051F series has more pins, up to 64 or 100, and the Sakura spring is also much more powerful, and it is not cheap.

If you are not familiar with the microcontroller, you can use the ordinary 40-pin 51 microcontroller with latch to expand the IO port spine resistance.

If there are only a few pins, you can choose the ordinary enhanced Tan Quiet 51 microcontroller, 44 pins or 48 pins.

The IO port of the MCU is used to define the input and output status and mode of the corresponding IO port. It includes three basic items: data vector data, attribute vector attribution and direction control vector Each corresponding bit in each port is combined together to form a control word, and the single-chip microcomputer switches the control word or the packaged control word reading in a dual way.

It is the output and input port, and the IO port of the single-chip microcomputer is bidirectional, which can be used as both input and output. For example, when connected to a button, it is used as an input port, and when connected to a light-emitting diode, it is used as an output port.

It can be used as a power supply, but the premise is that the power cannot be too large, that is, the current cannot be large, and the voltage may not be stable, it should be lower than the VCC voltage of the single-chip microcomputer, for example, you can use 51 IO to control the LED on and off, but if you control the motor is impossible, because if the current is large, it will burn the chip in turn, so if you can use IO to control the power supply, but you can't directly supply the power. Three-state gates can be considered for power supply control.

Connect a transistor or an optocoupler.