Pwm Driver - Freescale Semiconductor DSP56800E User Manual

5.14

PWM Driver

This section describes the API for the MC56F83xx and MC56F80xx Pulse Width Modulator
(PWM) on-chip module. The functionality of the PWM module itself is described in the
MC56F83xx Peripheral User Manual, 56F8000 Peripheral Reference Manual, 56F802x/3x
Peripheral Reference Manual and 56F800x Peripheral Reference Manual..
5.14.1 Introduction
The MC56F83xx and MC56F80xx devices have up to two PWM modules (PWMA and PWMB),
each with 6 PWM outputs, 3 Current Sense inputs and 4 Fault inputs, fault tolerant design with
Deadtime insertion, supports both center and edge aligned modes. The PWM module can be
configured for 1, 2 or 3 complementary pairs, the remaining outputs can then be used as
independent channels.
This section describes the PWM driver software providing the lowest level software layer,
interfacing the hardware with the software.
5.14.2 Quick Reference
This section is intended to be a source of quick access information while the details are discussed
in Section 5.14.3.
Module base address
of / for
PWM (PWM_BASE)
PWM A (PWMA_BASE)
PWM B (PWMB_BASE)
5.14.2.1 PWM Module Setting
The following expressions are useful for PWM module setting.
5.14.2.1.1 PWM Clock Calculation
PWM Clock Period = PWM Prescaler / IP Bus Clock Frequency
5.14.2.1.2 PWM Period and Frequency Calculation
for CENTER ALIGNMENT
PWM Period = PWM Modulus * PWM Clock Period * 2
for EDGE ALIGNMENT
PWM Period = PWM Modulus * PWM Clock Period
PWM Frequency = 1 / PWM Period
5.14.2.1.3 Deadtime Calculation
deadtime = (PWM Deadtime Reg. * PWM Clock Period) - 1 IP Bus Clock
(the one IP Bus Clock is not subtracted when PWM Prescaler is 1)
FREESCALE SEMICONDUCTOR
Table 5-445. PWM Module Base Address
MC56F800x MC56F801x
0xF020 0xF040
N/A N/A
N/A N/A
Targeting 56F8xxx Platform
MC56F802x/3x MC56F832x
0xF0C0 N/A
N/A 0xF140
N/A N/A
MC56F83xx
N/A
0xF140
0xF160
5-547