This article gives you almost all thing to build a micro controller programmer by yourself.........
The c series like 89C51 and 89C52cannot programmed with this gadget.
Only S series which support in-system -programming (89S51&89S52) could be programmed.
By seeing this circuit diagram you may get little confusion, but do not worry .
I will show you an easy way to construct this circuit (shown diagram is from Asim khans isp programmer).
- we dont need the interface buffer ic 74hct541 [it used here for cmos ttl logic voltage adaptation.commonly parallel port output shows ttl volt level,generally it wont do any harm to micro controller ]
- here 25-pin d connector is used to plug programmer to computer
- 5 volt power supply for microcontroll is taken from the USB port
MAIN COMPONENTS
- 25-pin D male connector
- 40-pin zif socket
- USB port male connector
- BC 557 transistor
- Directly connect the 5th pin of D-connector to the base resistor 3k3 of transistor 557 (intead of 3k3 can use 4k7 ).
- Directly connect the 6th pin of D-connector to 8th pin of zif.
- Directly connect the 7th pin of D-connector to 6th pin of zif.
- Directly connect the 9th pin of D-connector to 9th pin of zif, no need to replace the 10nf (.01 uf) capacitor let it be there.
- Directly connect the 10th pin of D-connector to 7th pin of zif.
- Connect pin 1,2,12,18 and 25 of D-connector to ground of the circuit.
- Power supply is from Usb
- Here we avoided the interface ic and some resistors placed left of it,, that is the component used for aid it only.