Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
microcontroller at89c52 becouse i want to make digital watch but i dont want to use decoder 7447 i want to connected all seven segment to one port is there any code or command that let the microcontroller send data to all seven segment but only the wanted no out on the wanted seven segment
Bear in mind that when the number of 7segments elements grows ( from 4 to 8 -) the current through LED diminishes, thus you have to decrease the value of resistors connected to port P1 ( 180R in the schematics **broken link removed** )
**broken link removed**
However, 89C52 it's not suitable to sustain the current (VOL = 0.45v for IOL = 3,2 mA), so you have to fit 7 pnp transistors on port P1 like the one on P3.7
@xfilesb ,
I guess that you are against using the 7447 decoder because of its power consumption. In such a case you can always get the CMOS counterpart. There are at least four types available. If you, however, are not happy with any decoder IC at all, there are still two possibilities for you. As suggested above, you can use serial In parallel OUT registers to handle your display, or you can build a BCD to 7-segment decoder using some silicon diodes and some transistors. This way your six digit display would use just seven pins of one uC port. It is the simplest solution I know, but not the most elegant one.
The choice is yours.
Regards, yego
You should use 6 8-bits Shift registers for 6 7Seg-LEDs, you can drive them easy by using series data communication method which don't need to use all pins of 1 port. Only 3 or 4 pins are enough.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
