Build your own a personal writer for programming HEX code into Flash based microcontroller AT89C2051,2k and AT89C4051,4k. Simple hardware and Easy use software in DOS and Window version. Single-side and double side PCB files included.
The circuit uses a 89C2051 with writer.hex firmware, 74LS373 8-bit latch, DS275-like, 7805, LM317 and two transistors, 2N2222A and 2N2907A. The programming voltage control circuit is the same as recommended by ATMEL application note. It can be raised from 0V, 5V and 12V by appropriated signal from P3. The 8-bit latch, 74LS373 provides some signal for selecting the programming modes. A byte to be programmed or read back is sent/received through P1. Incrementing address is done by pulsing a positive pulse to XTAL pin. The circuit may be built using simple point-to-point soldering with a general purpose PCB( fish’s egg like PCB) or making PCB shown above, the file is Easy-v1.pcb Protel PCB version 2.76. The finished board should be tested without any chips; 1) +5V supply, 2) programming voltage 0V, 5V and 12V by connecting the pin that control (P3.5 and D) 2N2222A and 2N2907 to +5V and/or GND. The adapter output should be approx. 15Vdc 100mA.
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