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Easy-DownloaderV1.1 for ATMEL89C2051

Build your own a personal writer forprogramming HEX code into Flash based microcontroller AT89C2051(2k) andAT89C4051(4k). Simple hardware and Easy use software in DOS and Windowversion. Single-side and double side PCB files included.sourcecode with sdcc version!


The first version of the Easy-Downloaderwas designed in 1997 to be used as a tool for my students on building her/hisown microcontrollers circuit in the class ” Designing Microprocessors System”.The circuit features low-cost and easy use. The latest version V1.1 wasdesigned to be used with 2051 and the newest 4051 chips. There is no separatefunctions like other programmer e.g., blank check, erase, write. Simplytype say, c:\..>ez hello , the hex file “hello.hex” will then be programmedto the chip automatically. If the chip is not blank or the code is locked,it will erase first, then write and verify… that all.



Figure 1 shows a circuit diagramof the Easy-Downloader. As shown, the circuit uses a 89C2051 with writer.hexfirmware, 74LS373 8-bit latch, DS275-like, 7805, LM317 and two transistors,2N2222A and 2N2907A. The programming voltage control circuit is the sameas recommended by ATMEL application note. It can be raised from 0V, 5Vand 12V by appropriated signal from P3. The 8-bit latch, 74LS373 providessome signal for selecting the programming modes. A byte to be programmedor read back is sent/received through P1. Incrementing address is doneby pulsing a positive pulse to XTAL pin. The circuit may be built usingsimple point-to-point soldering with a general purpose PCB( fish’s egglike PCB) or making PCB shown above, the file is  Easy-v1.pcbProtel PCB version 2.76. The finished board should be tested without anychips; 1) +5V supply, 2) programming voltage 0V, 5V and 12V by connectingthe pin that control (P3.5 and D) 2N2222A and 2N2907 to +5V and/or GND.The adapter output should be approx. 15Vdc 100mA.

AcrobatPCB Files

Assuggested by a friend from Romania, Puiu Chiselita, to provide PCB imagein Acrobat file, so I have asked my friend, Jaroon Keawkhrua. He made withinan hour, thanks again for providing us, the Acrobat PCB file.

TOPLAYER (80kB) easy-v2t.pdf
BOTTOMLAYER (36kB) easy-v2b.pdf
COMPONENTLAYER (51kB) easy-v2o.pdf


Two files that you shouldget are: writer.hex 4,871 bytes, the intelhex file firmware for 89C2051 chip ( the actual code size is 2021 bytes)and, ez.exe 20,800 bytes the uploader programrun on PC, send hex file to the downloader. The original writer.cprogram was written in ‘C’. To modify, it needs Micro C-compiler from DunfieldDevelopment System Ontario Canada with tiny memory model.

Functional Test

Use a given programmer (or readymade Easy-Downloader) write the writer.hex into the 2051 chip. Put theprogrammed 2051 chip to the board. Invoke any communication software with9600 baud, 8-data bit, no parity. Connect DB-9 to COM1, say, press enterkey, the title “Easy-Downloader V1.1 for ATMEL 89C2051/4051” would be appearedon the screen. type >s2048 ( set byte counter to 2k), then without the2051 chip in ZIF, type >r (read 2kB), on screen would show FFFFFFFFFFF…indicating corrected wiring for P1. If you put the chip having alreadyprogram inside, r command will show the hex code with the number of byteset by s command. Try e command to erase the entire program!! All done.Figure 2 shows example of using Xtalk program to test the board.

For more detail: Easy-DownloaderV1.1 for ATMEL89C2051

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