Digital-to-analogue conversion method based on PWM (pulse width modulation) pin of DSP (digital signal processor)

[0021] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0022] see Figure 1-3 , the present invention connects resistance R at PWM pin output inside DSP, connects a capacitance C between resistance R and circuit GND, and the common connection point of resistance R and capacitance C is output; Inside DSP, digital quantity A_wave is a time The quantity that has been discretized in terms of magnitude and amplitude, if the digital quantity corresponding to each time point is assigned to the comparison register inside the DSP, then the value in the counter (defined as the continuous increase and decrease counting mode) is equal to When the digital quantity of A_wave at this moment (this value is called the comparison match point), the specified PWM pin will output the corresponding level. see figure 1 It is stipulated that the output PWM pin is set to high level when the comparison matching point A is