AVR microcontroller fuse configuration is very easy for AVR microcontroller beginners where error-prone, in fact, as long as you pay attention to some matters, or can try to avoid the microcontroller is locked, even if the microcontroller is locked, you can use some methods to unlock, this article tells me Some problems occurred in the configuration of fuses when they first touched the AVR microcontroller.
1, AVR microcontroller fuses are unique features, can control the system clock, JTAG debugging, watchdog, chip encryption, and so on. Figure 1 is progisp software, for beginners, is not familiar with the fuse position, you can first remove the 2 programming fuse check hook, so that when programming, it will not be programmed on the fuse, the microcontroller factory The default settings can be used. Click 1 to enter the fuse configuration interface.
figure 1
Figure 2 shows the bit configuration mode, where each bit can not be clicked randomly, especially where the low-level fuses control the clock. In general, it is not safe to directly configure the bit. It must be the fuse that you want. Configuration can, if you accidentally moved the fuses, you can read or default, restore the fuse configuration, so that after downloading the program, it is safer.
Figure 2 bit configuration
Figure 3 shows the wizard mode. There are text descriptions, checkmarks are options, such as enabling the JTAG interface, enabling ISP programming, etc. It is recommended not to move these two. If you disable the ISP programming and JTAG interface at the same time, it will not be downloaded. program. The most important place is the configuration of the clock, Figure 4, the development board just bought, generally wearing a crystal, this time do not just choose the clock, if the board has an external crystal, and you have chosen the internal RC oscillator , This will directly lock the microcontroller, the same reason, if you choose the external crystal, but the external crystal oscillator is not installed, will lock the microcontroller. Therefore, the clock must be determined when configuring the clock.
Figure 3 Wizard mode
Figure 4 Clock
After confirming the configuration of the fuse, you can download the program. When debugging the program, you may download the program several times. After the fuse is correctly configured for the first time, you can program the fuse to be removed, just in case.
2, after the microcontroller lock methodAfter the microcontroller is locked, there are generally several ways to unlock it.
First, high-voltage programmers, where you need to buy high-voltage parallel programmers, beginners generally do not have this thing.
Second, if you have played 51 single-chip microcomputer or there are 51 single-chip microcomputers around friends, you can use 51 single-chip microcomputer to unlock, to 51 single-chip power supply, make it work, the 51 single-chip ALE pin leads out, plug in the AVR microcontroller crystal XTAL1 pin, click on the automatic under the progisp software, this time will unlock the AVR microcontroller, and then configure the correct fuse position on it (this method test is successful).
The third is to use an active crystal oscillator. If there is an active crystal oscillator at hand, this is the most convenient method of unlocking. In Figure 5, the small dot is on the bottom. Connect the OUT to XTAL1 and program under progisp. Can be unlocked directly. (Test successful)
Figure 5 Active Crystal
In addition, it is also possible to generate 1M above waves through an oscilloscope and generate square waves through other MCUs. These methods have not yet been attempted.
Figure 6
Added: When selecting the chip, it must be correct, otherwise ID identification error will occur. If this happens, do not select Yes, select No, and then check the signal and line connection of the chip.
Ethernet cables connect devices such as PCs, routers, and switches within a local area network.Most technicians refer to these standards as CAT5 and CAT6, respectively. Also CAT3 available. Because of this, many online stores that sell network cables use this abbreviated language as well.
The connector can by shield or non-shield type, raw cable can be UTP, STP, FTP type. Also the molded shape can be custom mould by straight, right-angle, 105 degree, etc.
These physical cables are limited by length and durability. If a network cable is too long or of poor quality, it won't carry a good network signal. These limits are one reason there are different types of Ethernet cables that are optimized to perform certain tasks in specific situations.
Ethernet Cable Wiring,RJ45 cable,networking cable,8P8C cable
ETOP WIREHARNESS LIMITED , https://www.wireharnessetop.com