Microcontroller having a digital to frequency converter and/or a pulse frequency modulator
A microcontroller having digital to frequency converter and pulse frequency modulator capabilities. The digital to frequency converter (DFC) generates a 50 percent duty cycle square wave signal that may be varied in frequency, wherein the 50 percent duty cycle square wave signal is directly proportional and linear with a count value put into an increment register. The pulse to frequency modulator (PFM) generates pulses having pulse widths of the input clock for each rollover of a counter. The frequency of these pulses is directly proportional and linear with the count value put into the increment register.
1. A method for digital-to-frequency conversion and pulse frequency modulation with an integrated circuit microcontroller having a timer/counter and an increment register, said method comprising the steps of:
providing a count-value in the timer/counter;
providing an N-value in the increment register;
adding the count-value and the N-value, then storing the result in the timer/counter at each one of a plurality of clock pulses;
selecting a high-order bit of the timer/counter for the digital-to-frequency conversion; and
selecting a carry-out resulting from the step of adding for the pulse frequency modulation.
2. The method according to claim 1 , further comprising the step of storing the N-value in a slave register.
3. The method according to claim 1 , further comprising the step of inverting the digital-to-frequency conversion and the pulse frequency modulation.
4. The method according to claim 3 , further comprising the step of generating a dead band between the digital-to-frequency conversion and the inverted digital-to-frequency conversion.
5. The method according to claim 3 , further comprising the step of generating a dead band between the pulse frequency modulation and the inverted pulse frequency modulation.
6. The method according to claim 1 , further comprising the step of synchronizing the plurality of clock pulses to an event.
7. The method according to claim 1 , further comprising the step of pre-scaling the frequency of the plurality of clock pulses.
8. The method according to claim 1 , further comprising the step of writing data to the increment register with a central processing unit of the microcontroller.