Pharma R&D materials HS code verification

List of the contents of this article:

• 1,Pharma R&D materials HS code verification 51 reinstall system How to make a boot disk
• 2, 51 single-chip microcomputer minimum system reset circuit
• 3, In the MCS-51 system, if the crystal frequency is repeatedly 8MHz, a machine cycle is equal to
• 4, vivoY51 system upgrade failsWhat to do
• 5, How to exit the 51 reinstall system
• 6, 51 Detailed explanation of single-chip microcomputer minimum system

51 Reinstall the system How to make a boot disk

1. Insert the USB flash drive into the computer, restart and keep pressing Del or F2 or F1 or F10 or esc and other keys to enter the BIOS interface. Under the boot item selection menu interface, select the usb item and press the Enter key to enter USB flash drive reinstall page. Reinstalling the system can solve some problems caused by viruses and various system problems for unknown reasons.

2. [Start] - [Write to hard disk image] After clicking, the write dialog box appears.

3. For example, the "run dos9img" command is used to start Windows 98. Since we made the Windows XP Pro boot disk, we should enter "Install Windows XP Pro", and enter "run w2ksect.bin" in the "Execute Command" column.

51 single-chip microcomputer minimum system reset circuit

Reset is to maintain at least two RST pins at a high level (usually above 0.7Vcc) under other working conditions of the 51 minimum system. The machine clock is to guide the single-chip microcomputer to reset, and then the RST pin is restored to a low level. Measures include: power-on and reset: give RST a high-level pulse after powering.

The size of the polar capacitance C1 of the minimum system reset circuit of the single-chip microcomputer directly affects the reset time of the single-chip microcomputer. Generally, 10~30uF is used. The larger the minimum system capacity of 51 single-chip microcomputer, the shorter the reset time required.

Clock circuit 51 Clock pin on single-chip microcomputer: XTAL1 (19 pins): chip internal oscillation circuit input. XTAL2 (18 pins): the output of the oscillation circuit inside the chip.

MCS-51In the system, if the crystal frequency is repeatedly 8MHz, a machine cycle is equal to

1, and the system needs to divide the frequency of 12, that is, the system frequency Fsys=8/12=(2/3)MHz=(2/3)*(10^6) Hz. So the machine cycle T=1/Fsys=(3/2)*(10^(-6)S=5us. That is, 5 microseconds.

2. Because it is stipulated that a machine cycle is 12 oscillation periods, and the oscillation period is the inverse of the oscillation frequency fosc, a machine cycle = 12/fosc, when fosc = 8MHz, substitute into the formula, the machine period is 12/(8MHz)s, that is, 5us .

3. In the MCS-51 system, a machine cycle is equal to 5μs.

4. Some enhanced 1 machine cycle = 1 clock cycle (or oscillation period), such as stc12 series, stc15 series 51 single-chip microcomputer machine cycle = / crystal frequency; when crystal frequency = 10592MHz, 1 machine cycle = 12 clock cycles (Or oscillation period), the machine cycle = 12/10592 microseconds.

5. In the MCS-51 single-chip microcomputer, when the crystal frequency is 6MHz, a machine cycle is 2us. It takes a machine cycle of 2us to execute a shortest instruction, and the longest instruction is 8us.

What to do if the vivoY51 system fails to upgrade

1. Restart the mobile phone and try it.Check whether the mobile phone is connected to the Internet normally, or switch the network to try, and then download the system package. Enter Settings--More Settings--Restore Factory Settings--Restore All Settings. This operation will not lose data.

2. Enter the vivo official website service, pull down to find the mobile phone upgrade, enter the mobile phone upgrade interface, find the y51 model, enter, click the resource download, select the corresponding model download, click the resource download, and then download the corresponding firmware upgrade package (full package) under the firmware upgrade, you can note The name of the upgrade package.

3. Otherwise, it is recommended not to upgrade to the current version for the time being. The reason for the prompt "invalid application file": This situation may be caused by several situations: incomplete application file download; APK file missing;The software is incompatible.

How to exit the 51 reinstall system

The uninstall steps are as follows. Turn on the butler function that comes with the Guardian software in your computer. Then find the "51 Simulator" in the "Uninstall" interface of the butler, and then click "Uninstall" and follow the prompts to uninstall it.

If you accidentally use the 51 reinstall system, causing the ASUS tablet to fail to start normally or have other problems, you can consider restoring the factory settings. The method is as follows: Shutdown: First, please turn off the power of the ASUS tablet.

In general, this situation may be that you have inserted the USB flash drive to install the system. You can unplug the USB flash drive and restart it directly or set it to hard disk to start.

Ctrl+Alt+Del, if it doesn't work, just hold down the power key to force the shutdown, and then reinstall the operating system according to the installation method after the computer restarts. If you have formatted the system disk and then exit the installer and restart it, you will not be able to enter the system. It has caused irreversible consequences.

OK. The computer failed to reinstall the system. If it is not installed, it will be forced to restart. You can press the power to turn it off. Or directly use ctrl plus del plus rt. Restart. However, if you restart, you may not be able to enter the system.

51 single-chip microcomputer minimum system detailed explanation

The oscillation frequency of the single-chip microcomputer minimum system crystal oscillation directly affects the processing speed of the single-chip microcomputer. The higher the frequency, the faster the processing speed.For a complete electronic design, the first problem is to provide a power supply module for the whole system. The stability and reliability of the power supply module is the premise and foundation for the smooth operation of the system.

The smallest system of a single-chip microcomputer, also known as the smallest application system, refers to a system that can work on a single-chip computer composed of the fewest components. For the 51 series single-chip microcomputer, the minimum system should generally include: single-chip microcomputer, power supply, crystal oscillation circuit, reset circuit.

The single-chip microcomputer minimum system, or the minimum application system, refers to a system that can work with a single-chip microcomputer composed of the fewest components. For 51 series single-chip microcomputers, the minimum system should generally include: single-chip microcomputer, crystal oscillation circuit, reset circuit.

The smallest system of a single-chip microcomputer is necessary to form a single-chip microcomputer system.Some components are composed of power supply circuit, clock circuit and reset circuit in addition to single-chip microcomputer. The minimum system circuit of the single-chip microcomputer (the power supply and ground of the single-chip microcomputer are not marked) is shown in Figure 2-7.

The following is a detailed description of the circuits of the smallest single-chip microcomputer system shown in Figure 2. Clock circuit Before designing the clock circuit, let's first understand the clock pin on the 51 single-chip microcomputer: XTAL1 (19 pins): the input terminal of the internal oscillation circuit of the chip. XTAL2 (18 pins): the output of the oscillation circuit inside the chip.

Hello, it's my pleasure to answer your question: 51 single-chip microcomputer minimum system includes the following circuits: power supply circuit: provide the required power supply energy for the system; crystal vibration circuit: provide clock beat for the work of the system, that is, the clock period, like a human heart.Reset circuit: reset system.