Homemade AT89C51 programmer, at89c51 programmer

AT89C51 is the most widely used 8051 microcontroller. More importantly, it has the feature of repeated programming (FLASH). Under normal circumstances, it can be reprogrammed 1,000 times, which provides a cheap platform for beginners to experiment. In order to meet the hands-on needs of the majority of microcontroller enthusiasts, I spent half a month and consulted foreign materials to actually design and produce a simple AT89C51/52/55 microcontroller programmer. Due to different microcontroller programming timings, this programmer only supports ATMEL's AT89C51, AT89C52, and AT89C55 chips, and does not support Winbond or Philips compatible chips.
For many electronics enthusiasts like me who are not too young and started assembling 7-tube semiconductor radios in the 1980s, facing a microcontroller seems a bit frightening, but in fact I think it is even simpler than assembling a radio: The following Here is the hardware circuit diagram. With a little patience, you can use a breadboard to solder it.
In order to facilitate everyone's production, I simplified the circuit design:

Q2, Q4 and several surrounding components constitute a level conversion circuit. This saves a max 232 chip. In situations where the requirements are not high, this circuit can be used for microcontroller communication. can replace the MAX232.

Q1, R2, R4, DW2, four components provide the programmer with 12V voltage for programming. Among them, R4 and R2 constitute a voltage dividing circuit; usually, the 13th pin (P3.3) of the monitoring chip 89C51 outputs high level. Q1 is turned on, R2 (1K) pulls DW2 (12V) low. At this time, the DW2 voltage is divided by R4 and R2, about 3-5V; when writing the program, the output of pin 13 (P3.3) of the monitoring chip Low level, Q1 is cut off, and DW2 (12V) is directly sent to pin 31 of the burned chip to provide the programming voltage. The programming voltage of the programmer provided by ATMEL official website is adjusted by LM317, and uses two high-precision resistors. The circuit is complex and costly. This circuit has been proven to be very stable and reliable through hundreds of experiments by myself.
Power transformer It requires a 15V power supply, such as the common 3-12V DC adjustable power supply. Pay attention to the no-load voltage not being lower than 13V, and the filtering should be better, otherwise the programming may be unreliable.

The monitoring chip is installed with an IC holder. Find a programmer to program the monitoring program EZ51.HEX and then insert it for easy debugging. If you have difficulty purchasing a programming card holder, you can directly use an IC holder. After assembly, power on and check with a multimeter:
1. 7805 outputs 5V and the D2 power indicator light is on. (I am using 78L05 in the picture)
2. The voltage of DW2 is 3-5V.
4. Short-circuit the base of Q1 to ground, and the voltage of DW2 is 12V.
5. The voltage of pins 18 and 19 of U1 (89C51) is 2.2V and 2.1V. This voltage can be used as the basis for whether the circuit starts to oscillate.
The connecting cable should be a 9-to-9 serial port cable with one end male and one female. Note that some serial cables on the market have pins 2 and 3 crossed at both ends. It is best to use a multimeter to check whether there is a one-to-one correspondence. If you don't have a serial port cable, you can also disassemble an old-fashioned serial port mouse and make your own. Just connect pins 2, 3, and 5 at both ends. This circuit has no special requirements for components. The resistor uses 1/8W ordinary carbon film. The transistor I used is 2SA1015 and 2SC1815. In fact, many low-power tubes can be used, such as 9014 and 9015. Just need to pay attention to the difference in their pin arrangement. Diode 1N4148 can be replaced with 1N4004. In addition, it is best to select a 12V voltage regulator tube, and the accuracy requirement is within 5%. The 11.0592M crystal should be tested if possible. Some of the crystals sold on the market do not vibrate.

The programming software EZ31.EXE of this programmer has a very simple interface; it is fully compatible with WINDOWS9X-2000. There are only a few buttons, namely open file (SEND), read chip (READ), exit (EXIT), COM selection, encryption (LOCK CODE), and verification (FAST VERILY). Everyone will know after using it. Note that the upgraded version ez4.0 currently available for download automatically monitors the port number and chip. Easier to use!

Connect the power supply and serial port cable of the programmer, insert the programmed chip, click COM1 or COM2 (subject to the actual connection, in this case I connected COM2), the lower right corner of the window displays 89C51Found. At this time, you should see the signal indicator D6 lighting up every 2 seconds, indicating online work.

Select a hex file that needs to be programmed and start programming. If everything is normal, the interface displayed is as shown in the picture above.
Double-sided super small PCB; note that the monitoring chip is mounted on the reverse side. Therefore, the entire circuit board is only slightly larger than a matchbox, and it may be the smallest programmer you can see. Isn't it very beautiful?


Take a look at this picture: You must have figured it out! There are less than 30 parts in total, which is really cool. It only takes half an hour to assemble one piece, from plug-in to soldering test.

Component
ListPart Type Designator Footprint
1K R19 axial0.3
1K R2 axial0.3
1N4148 D5 diode0.4
1N4148 D1 diode0.4
3K R3 axial0.3
3K R4 axial0.3
4K7 R13 axial0.3
4K7 R11 axial0.3
4K7 R8 axial0. 3
10K*8 R18 (row resistor)
10K R7 axial0.3
10K R6 axial0.3
10K R5 axial0.3
10UF C8 RB.2/.4
10UF C14 RB.2/.4
10UF C7 RB.2/.4
10UF C6 RB.2 / .4
11.0592M​​ ​1 104 C5 RAD0.1 A1015 Q4 to-126 C1815 Q1 to-126 C1815 Q2 to-126 IN4148 D4 diode0.4 LED D2 rb.2/.4 (light emitting diode) SINGAL D6 rb.2/.4 (light emitting diode) DB9 232 socket 40PIN programming card holder 40PIN IC socket (for plugging in monitoring chip) 232 serial line PCB 89C51 monitoring chip 15V power supply DIY installation steps: 1: Install resistors, 11 in total; after inserting the components in place, weld and cut the pins: 2: Installation Diodes, three 1N4148 and a 12V Zener diode DW2. Please look carefully at the words on the surface of the tube: the voltage regulator tube is printed with the words 12V, don’t get it confused. The diode is polarized. Just insert the black head of the diode toward the white printed side of the PCB: After the components are inserted in place, solder the scissor pins: 3: Install 2 104 and 2 30p capacitors; 11.0592 crystal, these There is no directionality, just plug it in: 4: Insert the transistor. Electrolytic capacitors, light-emitting tubes: Note that these things have polarity: it will not work if they are reversed. Electrolytic capacitors and light-emitting tubes are easy to handle, as they both have the negative pole facing downwards. Transistors (two 2SC1815, one 2SA1015,) and a 78L05 voltage stabilizing IC: their direction can be seen on the PCB, the direction of the butt is the direction of the semicircle. 5: Insert the resistor (the end with a white dot on the resistor is the common end, and its position is at the end close to the PCB side source; the power socket, needless to say, the 232 socket. 6: Plug in the socket of the monitoring chip. 7: Plug in The programming card holder is face to face with the monitoring chip, so the monitoring chip socket must be soldered first, and then the programming card holder will be difficult to use. 8: If you really can't figure out the direction of the component. Please keep your eyes open and take a closer look at the photos above. 9: Finally, check whether there are any wrong insertions or short circuits in various places on the circuit board. If there are no wrong insertions, you can basically adjust it in one go.