The upgraded part is only the PCB,the software remains the same as in original project which you can findat EasyDownloader V 1.1 Here you have a single side versionof PCB of the Easy-DownloaderV1.1 by WichitSirichote. The board is 10x4cm in a full size. That newPCB has some small modifications comparing to original scheme. It has anMAX232(or similar) instead of DS275, one LED (green) for 5Vcc indicating(instead of straight voltage in), also one LED for write process(red LED on the right top of PCB), one DB9F connector for serialaccess (can connect here a serial DB9F to DB9M cable [3 wires, pin 2 topin2, pin 3 to pin 3, pin 5 to pin 5] - that connector can be removedif not needed, board can be cutout following the light blue line betweenthe DB9F connector and rest of the board, in that case you will solderthe wires on 3 pins small RS232 connector which is in the top-left sideof the board), reset switch for Master uC (can connect a switch at X1 SIPconnector (top middle) for reset operation).
All can be easy done in ONE SIDE PCB with only 3 short straps! I recommendto print the GIF picture (using a laser printer at least 300DPI) at rightscale (you can do some experiences on normal paper to find the correctscale for printing [you can place over the holes on the paper an 20 pinsIC to see if it match over the holes, once is matching, the other partswill also do, and you can print it and print it on a full transparent UVsheet of plastic (transparent plastic sheet for laser printers will beOK) and than, using the Positive spray technology (spray, UV exposure,developing, etching), to transfer the GIF on the copper side of board (theGIF is bottom side view from top, so, turn it [mirror] before put it onboard).
Also, the board can be done by hand draw, taking care about inter-pinscrossing tracks. Take care for short circuits! A good idea is to mountall ICs on sockets (not only the slave uC, but also the rest), in thatcase if something is going wrong is very easy to replace the defectivepart! Also, there are 2 parts (R11 and D4) which are mounted under theMaster uC, so you can mount them below (inside) the uC socket or, if notpossible, you can mount them on the other side of PCB (bottom side).
The power supply for the programmer is somewhere at +15Vcc and the inputis protected with a 1N4001 diode for reverse polarity. Around LM317 are3 resistors which require very precise values, I had not, so, I tried andcombined several parts until I measured right voltages (+12Vcc +/-0.5 when2N2222 is OFF and +5Vcc +/-0.1 when 2N2222 is ON), you can also put 2 potsinstead of R2 and R3 (5k and 2.5K pots). Better disconnect powersupply before manipulating uC! Also, Zener diode between base of 2N2907and ground is optional (if it exist, we'll have always 12Vcc/5Vcc on pin1 of ZIF socket, so, better without; reason for that diode is to stop the12Vcc go to LS373, but not necessary). LS373 chip is pin 1 down (!), causeof easier PCB in this way...
Figure 1: Circuit Diagram of Easy-DownloaderV1.2
Figure 2: An PCB Overviewfrom component side [click to enlarge]
(blue=bottom layer, red=top layer or straps,yellow=components[silkscreen overlay])
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Figure 3: PCB bottom layer overview(from component side) and holes (185 pads)
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Figure 4: Bottom layerin 2 colors, ready for printing
Click on image for good resolution GIF readyfor printing
Bottom layer is viewed from component side(top)
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Figure 5: An componentsside overview, straps (or top layer=red) and components values
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Figure 6: An ready-to-run board overview
Also here you have the PCB (Protel 2.7.1) easypuiu.pcb
Here is the BIN filefor AT89C2051 Master
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