Hi all,
I am working on a project that should generate a 0-5V pulse with
· user configurable frequency (0 - 100KHz )
· user configurable duty cycle(0% - 100% )
· user adjustable phase (w.r.t. each other)
· Four such outputs that are independently controllable

Besides, user should be able to adjust the frequency, duty cycle and phase via serial communication (instead of burning program on microcontroller each time he selects different values of these parameters).

I already have a circuit that generates PWM. This circuit takes in 5 bit digital input and generates a pulse of duty cycle depending on the digital input. The frequency can be varied at the same time by using variable frequency generator (which is used as a clock to above circuitry). The PWM waveform frequency is proportional to clk frequency.

I have AT89S52 board with 11MHz crystal on it and wish to use it to generate variable frequenies and four such (variable frequency) outputs that are independently controllable by user Can anybody help me with a code for this and a circuitry that can generate four outputs.
Thanks,
Nilesh