Exactly as the question says. On the TI 555 Rev. C data sheet, what is the modulation input for the PWM circuit? Also, can I round the resistor and cap. to 10k and .022uf, respectively?
The modulation input can be used to raise the charging potential for the capacitor. This means if you take pin 5 above where it normally sits (two-thirds Vcc from memory) the frequency will reduce if configured as an astable and the time delay will increase if used as a monostable.
You can round any component value to any other but, whether it will work as you require that's a different story. Show a circuit if you want a more useful answer.