at89c51 DIY Programmer(English)

Published:2011/4/25 2:10:00 Author:Ecco | Keyword: DIY , Programmer | From:SeekIC

Figure 1 shows the circuit diagram of the Flash Programmer, the programmer is interfaced with the standard parallel port of the PC. As shown in the diagram U2 is used to control the data flow between the controller and the PC, U4 latched the low order address byte and U5 latched the high order address byte, while U3 is used to generate the control signals for micro controller to be programmed. IC U1 is used to generate the progrram pulse for the u-controller. The power supply section uses U8 to generate the logic 5V supply while the U7 is used to provide the programming supply voltage to controller. IC U6 is used to generate the VDD power supply voltage for the u-controller which is selectable either 5v or 6v5. The power to the circuit is provided by a wall adapter of 15 to 18V output, normally a 15V type adapter will provide a 19~20V output voltage. As shown in the diagram the crystal X1 can be replaced by a resonator in that case capacitors C4 and C5 are not required. Place a small heatsink on U8 voltage regulator. For the adjustment of P1, P2 and P3 use a digital multimeter & follow the steps shown below, 1. To adjust P1, temporarily connect T1 base to ground using test clips then adjust P1 to get 6.5V at the output of regulator U6.2. Next first adjust P2 to get the 13.1V at the output of regulator U7, make sure transistor T5 is off or temporarily connect the T5 base to ground using test clips.3. Now temporarily short the collector of transistor T5 to ground using test clips.3. Adjust P3 to get the 12.1V at the output of U7 regulator IC. Figure 2 shows the circuit diagram of the interface adapter card required for the programming of 20 pin Flash devices. Pgm89v3.zip file is used to run the programmer. This is a Windows program which can be used underWindows 95 & 98. The main screen of the program is shown in figure 4. In order to insure safe insertion & removal of the u-controller from programmer ZIF socket make sure programmer power supply is turned on before starting the program and the red LED D1 must be turned off when the program is started. The u-controller should be placed or removed from the ZIF socket when the red LED D1 is off.Also note that the software does not provide the erase command because this function is performed automatically during device programming. If you are required to erase the controller first use the clear buffer command in edit menu then program the controller, this will erase the controller memory.



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