The Atmel AT89C is a low-power, high-performance 8-bit microcontroller compatible with the MSC instruction set and object code. This report describes a construction analysis of the Atmel AT89C and the. AT89S 8-Bit Microcontrollers. Ten AT89C devices encapsulated in . The AT89CPU is a low voltage, high performance CMOS 8bit microcontroller in 20 pin DIP package. The device is manufactured using Atmel’s high.

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Increment address counter by pulsing XTAL1, set next instruction code via P1 Repeat steps 5 to 8 until the 2kB boundary is reached, or until the whole file has been programmed into the chip. Port3 bits can also sink up to 20 mA of current, and when written with ones, can be used as inputs.

Instead of waiting 1. This programmer is a part of the LAB system. With the AT89C51, it is not even possible to transfer contents of the internal FLASH memory if an external memory with a special software is attached to it.

A done flag that indicates the end of operation. Figure 3 at899c2051 the circuit schematic for the mictocontroller.

Atmel’s AT89C2051 Microcontroller

It should work with no problem on the first try. The interface is ideally suited for data acquisition on PC compatibles using the parallel printer adapter signals. After the code is burnt into the chip, the programmer power supply is turned off before removing the target chip. The target chip is then ready to be inserted into the target system. Figures 1 and 2 show the block diagram for programming and verifying the Flash-memory contents of an AT89C It was designed using common components, with respect to simple construction.

We are working on a reprint. After the controller has been programmed, to reprogram any nonblank byte, the entire chip has to be electrically erased. An external clock source with suitable levels can also be used instead of a crystal or a resonator. Data reading and verification is controlled by circuit – four multiplexers, allowing to read 8 bits via four parallel port input bits. The controller programs miceocontroller serial port as an output shift register in the beginning of the acquisition cycle during which the MAX needs the 8-bit control byte that contains conversion parameters, channel number, and so on.


The Atmel application microconttroller describe a simple programmer that lets you perform a variety of operations with the flash controller, including erasing, reading, programming, and verifying the contents of the target chip see http: Instruction compatible with MCS In some cases, it’s better to use a different design for the voltage st89c2051 part – see the end of this article.

To communicate with the BASIC system, the terminal emulator can use any standard baud rate as well as transmission settings number of bits, parity, and so on. I found that the AT89C worked well. Optionally, set verification mode via bits P3. After I was satisfied that things were working, I went ahead with more serious applications. There is no further significant power consumption drop at lower clock frequencies.

This is one of the simplest programmers. Thus, it is possible to port existing applications to an AT89C without change to the micocontroller code — as long as the software limits itself to the available hardware resources, including memory and ports. As Table 1 shows, Port3 pins P3.

AT89CPU – AT89C Pin 24MHz 2kb 8-bit Microcontroller Technical Data

Figure 4 shows the block diagram, and Figure 5 see page 55 shows the circuit schematic. It’s a pity it can’t run just with a RC-circuit for clock signal generating, and that an OTP version is not available. Use as controllers in portable instruments is further simplified by the low power consumption and wide operating voltage range.

Data protection system is designed very well. My objective was to build a simple programmer, that would be easy to make at home and would work without significant problems on the first try.

A clear-status input that is used to erase previous status information. The code memory is programmed one byte at a time. By writing ones to the Port1 bits, they can be used as input bits. The mode input to the converter determines what task the controller will perform microcontrollfr it is triggered.


Due to undefined state of the LPT port after running some mcirocontroller, it is necessary to turn on the power for the programmer AFTER starting the control software.

Its output is accessible to the software via the P3. Set the programming mode via pins P3. The AT89C data sheet states that the on-chip oscillator can be used with a ceramic resonator as well as a resonant crystal element to provide the basic clock to the microcomputer. If you need more exact specifications, download the original datasheet in. Subsequently the system is loaded with the code in Listing One from within micrcoontroller terminal-emulator environment.

We paid great attention to the timing routines, so it should work on any computer. The microcontroller serial port operates in mode 0, in which the serial port works as a shift register, either as input or output. Figure 6 shows the wiring scheme to connect the controller board to the PC printer adapter.

Both software versions support so-called DEBUG mode, that should greatly simplify any troubleshooting. It connects directly to a PC parallel port.

You can view the modified schematics at89c251. The AT89C microcontroller can endure one thousand program and erase cycles. For this design, only 11 combinations are required; the rest can be used later for expansion.

It is definitely better to use two 8-bit “D” flip-flopswhich are triggered by edge, not by level. The only major inovation over standard series processors is the analog comparator on pins P1. Big thanks to the author. Erasing the chip is a simple task that takes a few milliseconds to execute. However, the driver software for the programmer does not support IntelHex object files.