The 803 1 chip has no program memory ROM, so users need to connect the program memory and a piece of logic circuit 373 when using it. Most external program memories are 2764 series EPROM. If the user wants to modify the program written in EPROM, he must erase it with a special ultraviolet lamp before writing. The program code written into the additional memory has no confidentiality.
2.805 1
805 1 chip has 4k ROM, which better reflects the simplicity of "single chip" without external memory and 373. However, you can't burn your compiled program into its ROM. You have to give it to the chip factory for you to burn, and it's disposable. Neither you nor the chip factory can rewrite its contents in the future.
The function of 3.875 1
875 1 is basically the same as 805 1, but there is a 4k EPROM in 875 1. Users can write their own programs into the EPROM of single chip microcomputer for field experiments and applications. The rewriting of EPROM also needs to be erased by ultraviolet lamp for a certain period of time before burning.
Due to the early application and great influence of the above-mentioned types of single-chip microcomputer, it has become a de facto industrial standard. Later, many chip manufacturers cooperated with Intel in various ways and also introduced the same type of single chip microcomputer. Like multiple versions of a single chip microcomputer, although the manufacturing process is constantly changing, the kernel is the same, that is to say, this single chip microcomputer instruction system is completely compatible, and most pins are also compatible; Basically, they can be directly used interchangeably. People refer to these single-chip computers with the same kernel as 805 1 as "5 1 series single-chip computers". If you learn one of them, you will know all the 5 1 series.
4. Characteristics of at89c 5 1 and AT89C51
Among many 5 1 series single-chip computers, AT89C5 1 and AT89S5 1 of ATMEL Company are more practical, because they are not only completely compatible with 805 1 instructions and pins, but also the 4K program memory on the chip is FLASH technology, which can be instantly erased and rewritten by users, and is generally designed for Atmel AT. Obviously, this kind of single chip microcomputer has very low requirements for developing equipment, which greatly shortens the development time. The program written in the single-chip microcomputer can also be encrypted, which protects your labor results well. Furthermore, at present, the prices of AT89C5 1 and at89c 5 1 are lower than 803 1, and the market supply is also sufficient.
AT89S5 1 52 is a new variety introduced by ATMEL in 2003. Besides being fully compatible with 805 1, they also have ISP programming and watchdog functions. We also specially designed a programming, learning and experiment board for this new film.
5. The characteristics of AT89C2051,AT89C 105 1, etc.
ATMEL's 5 1 series also includes AT89C205 1, AT89C 105 1 and other varieties. These chips are simplified versions formed by simplifying some functions on the basis of AT89C5 1. In AT89C205 1, the P0 port and P2 port are removed, the internal program flash memory is also as small as 2K, and the package form is changed from P40 pin of 5 1 to 20 pin, and the corresponding price is also lower, which is especially suitable for some smart toys, handheld instruments and other circuit environments with small programs. AT89C 105 1 On the basis of 205 1, the serial port function is simplified again, and the program memory is reduced to 1k again, of course, the price is lower.
For 205 1 and 105 1, although some resources are reduced, a precision comparator is integrated. Don't underestimate this small comparator, it provides great convenience for us to measure some analog signals. In the case of adding a small amount of resistance and capacitance, it can measure daily needs such as voltage and temperature. This is a valuable resource for the design of many household appliances.
ATMEL's 5 1, 205 1, 105 1 have various packages, such as AT89C(S)5 1 with PDIP, PLCC, PQFP/TQFP packages. 20511051packed in PDIP and SOIC. The picture below is a part of the package.
Because the cores of 5 1 series single-chip computers are all the same, the books of Intel MCS 805 1 single-chip computers are still used in the teaching materials of 51single-chip computers. The same is true for developing software and tools. We collectively call it 805 1 to develop systems, environments and so on. For example, assemblers ASM5 1, Keil C5 1, MedWin, etc. What is introduced on our website is to develop software for 805 1 kernel single chip microcomputer.
For AT89C5 1 and at89c 5 1, in the actual circuit, 8051/8751can be directly interchanged, and 803 1 is only replaced by 3 1 pin. Because there is no ROM in it, 803 1 is different. However, 8051/8751/89c51has a program memory inside, and the pin of 3 1 is connected to high level (VCC), so the single chip microcomputer can directly read the instructions inside after starting. That is, 3 1 pin of 5 1 chip controls whether the MCU program is read from inside or outside, 3 1 pin is connected with power supply, and 3 1 pin is connected with ground, and the program is read from outside. Others don't need to be changed. In addition, after AT89C5 1 and at89c 5 1 replace 803 1, there is no need to install the external memory and 373 chip of the original circuit.
6.89S5 1 and 89C5 1
MCS-5 1 Single Chip Microcomputer is a product of 1980, which was introduced by INTE Company in the United States. Typical products are 803 1 (there is no program memory inside, which has been eliminated by the market in actual use) and 805 1 (the chip adopts HMOS, and the power consumption is 630mW, which is five times that of 89C5 1). Actual use has been eliminated by the market) and 875 1, and so on. Up to now, MCS-5 1 single chip microcomputer compatible with kernel series is still the mainstream product (such as the popular 89S5 1 and 89C5 1, etc. ), and the training materials of colleges and professional schools still use MCS-5 1 single chip microcomputer. Some documents even refer to 805 1 as MCS-5 1 series single chip microcomputer. 805 1 is the most typical representative work in the early days, and MCS-5 1 kernel has actually become the standard of an 8-bit microcontroller.
Other companies' 5 1 MCU products are compatible with MCS-5 1 kernel. The same program runs on the hardware of various MCU manufacturers, and the results are the same, such as ATMEL's 89C5 1 (discontinued), 89S5 1, PHILIPS (Philips), WINBOND (Winbond) and so on. The discontinued 89C5 1 we often refer to AT89C565454 of ATMEL. At the same time, many functions have been enhanced on the original basis, such as clock. Better still, the original ROM (write once) is taken from Flash (the contents of the program memory can be rewritten at least 1000 times), and the performance of AT89C5 1 is already very superior to that of 805 1.
However, in terms of marketization, 89C5 1 has been challenged by PIC MCU camp. The most fatal defect of 89C5 1 is that it doesn't support ISP (online update program) function, and new functions such as ISP function must be added to better continue the legend of MCS-5 1. In this context, 89S5 1 replaced 89C5 1. Now, 89S5 1 has become the new favorite in the practical application market. Atmel, which has the largest market share, has been discontinued and will be replaced by AT89S5 1. 89S5 1 has been improved in technology. 89S5 1 adopts 0.35 new technology, which reduces the cost, improves the function and increases the competitiveness. 89SXX can be compatible with 5 1 series chips such as 89CXX. At the same time, Atmel no longer accepts orders for 89CXX. The 89C5 1 you see in the market is actually a huge inventory produced by Atmel in the early stage. Atmel can certainly resume production of AT89C5 1 if the market needs it.
7. Compared with 89C5 1, the new functions of 89S5 1 include:
1) performance is greatly improved, and the price is basically unchanged, even lower than 89C5 1!
2)ISP online programming function, the advantage of this function is that the program can be rewritten in the memory of single chip microcomputer without stripping the chip from the working environment. Is a powerful and easy-to-use function.
3) The highest working frequency is 33MHz. As we all know, the limit working frequency of 89C5 1 is 24M, which means that S5 1 has a higher working frequency, so the calculation speed is faster.
4) It has duplex UART serial channel.
5) The watchdog timer is integrated internally, so it is no longer necessary to connect the watchdog timer unit circuit like 89C5 1.
6) Double data indicator.
7) Power off sign.
8) The brand-new encryption algorithm makes * * for 89S5 1 at a loss, which greatly strengthens the confidentiality of the program, thus effectively protecting intellectual property rights from infringement.
9) Compatibility: fully compatible with 5 1 full-word series products. Such as 805 1, 89C5 1 and other early MCS-5 1 compatible products.