just wanna know what is the minimum and maximum number of input and output of a microcontroller... is there a micro controller that has 20 input and output...
Minimum : probably 1
Maximum : probably a few hundreds
A lot of microcontrollers have at least 20 digital I/O pins... Do a parametric search on Microchip's website for PIC16 and PIC18 families. You will get plenty of results.
Atmel, Philips, Motorola/Freescale, Analog Devices, Texas Instruments, etc. all have such microcontrollers...
just wanna know what is the minimum and maximum number of input and output of a microcontroller... is there a micro controller that has 20 input and output...
Ofcourse there is, for example 16F876, 16F877 or 18F2xxx or 18F4xxx. They are packaged in 28 or 40 pin packages and should have sufficient number of pins for all regular designs.