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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Figure 6 shows the wiring scheme to connect the controller board to the PC printer adapter. Consequently, I decided to build a general-purpose interface that could be used in other applications. The AT89C microcontroller can endure one thousand program and erase cycles. Set the programming mode via pins P3. The interface is ideally suited for data miccrocontroller on PC compatibles using the parallel printer adapter signals. It connects directly to a PC parallel port.

AT89C can be operated with a clock frequency between 0 and 24 MHz.

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Thus, it is possible to port existing applications to an AT89C without change to the object code — as long as the software limits itself to the available hardware resources, including memory and microcontro,ler. A PC with an assembler and terminal-emulation program I use Vterm are the only tools required for programming and using the AT89C After the 8-bit data is shifted out, the controller micrcoontroller converts the serial port as an input shift register and reads back the converted ADC data as 2 bytes.

The AT89C can be programmed using a suitable programmer out of the target system. Micrcoontroller controller programs the 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.

Atmel’s AT89C Microcontroller | Dr Dobb’s

Due to undefined state of the LPT port after running some applications, it is necessary to turn on the power for the programmer AFTER starting the control software. Using an capacity controller to parallelize serial ADC data might be considered overkill.


Current nibble high or low is determined by the state of the 6Q bit pin 14 of the system latch It still works since Atmels sustain a lot; however, their opinion is included here simply because they are right. Using the Converter The converter interface is designed so that it can be used in any embedded application. The code memory is programmed one byte at a time.

I found I could modify an existing IntelHex loader program for the Basic system to get the required programmer code. After I was satisfied that things were working, I went ahead with more serious applications. The Atmel application sheets describe a simple programmer that lets you perform a variety of operations with the flash controller, including erasing, reading, programming, and verifying the contents imcrocontroller the target chip see http: For example, mkcrocontroller printing programs can do almost anything with the LPT.

A trigger input that triggers the converter into the requested mode. Instead of waiting 1. With the AT89C51, it is not even possible to transfer contents of the internal Microconrtoller memory if an external memory with a special software is attached to it.

The mode input to the converter determines what task the controller will perform when it is triggered. Figure 4 shows the block diagram, and Figure 5 see page 55 shows the circuit schematic.

Port3 bits can also sink up to 20 mA of current, and when written with ones, can be used as inputs.

After the hex file is successfully received, the programmer proceeds with erasing the AT89C, then begins programming it with the user object code. The original design used the circuit; however, its use did not prove to be useful due to the parallel port output design see the article about LPT. We paid great attention microcpntroller the timing routines, so it should work on any computer.


My good friend Dr. It also affords two software-selectable save-power modes. Two bit programmable timers.

The only disadvantage of this processor is a small and non-expandable program memory. This is possible because the chip uses static memory. There is no further significant power consumption drop at lower clock frequencies.

Atmel AT89C programmer |

After the code is burnt into the chip, the programmer power supply is turned off before removing the target chip. Erasing the chip is a simple task that takes a few milliseconds to execute. A clear-status input that is used to erase previous status information. After the controller has been programmed, to reprogram any nonblank byte, the entire chip has to be electrically erased. Low-power and power-down modes. With 4 bits of mode input, up to 16 modes see Table 3 of operation can be implemented.

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.

The analog input voltage range of the ADC is 0 to 4. The AT89C data sheet states that nicrocontroller 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. The received hex code is stored in the External RAM of the system. Port1 output buffers have a 20 mA sink current capacity and can drive LEDs directly. This means that all jumps ljmp and calls lcall must be limited to maximum physical address 0x7FF.

The target chip is then ready to be inserted into the target system. Its output is accessible to the software via the P3. Big thanks to the author.