MC68HC05V12 Datasheet, PDF (113/246 Pages) Freescale Semiconductor, Inc – HCMOS Microcontreller Unit

Freescale Semiconductor, Inc.
Technical Data — MC68HC05V12
Section 11. Pulse Width Modulators (PWMs)
11.1 Contents
11.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113
11.3 PWM Functional Description . . . . . . . . . . . . . . . . . . . . . . . . .114
11.4 PWM Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
11.4.1 PWMA Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . .117
11.4.2 PWMB Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . .118
11.4.3 PWMA Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119
11.4.4 PWMB Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119
11.5 PWMs during Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
11.6 PWMs during Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
11.7 PWMs during Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
11.2 Introduction
The pulse width modulator (PWM) system has two 6-bit PWMs (PWMA
and PWMB). Preceding the 6-bit (÷64) counters are two programmable
prescalers.The PWM frequency is selected by choosing the desired
divide option from the programmable prescalers. Note that the PWM
clock input is f_OP. The PWM frequency will be f_OP/(PSA*(PSB-1)*64)
where PSA and PSB are the values selected by the A and B prescaler
and 64 comes from the 6-bit modulus counter. See Table 11-1 for
precise values. The f_OP is the internal bus frequency fixed to half of the
external oscillator frequency.
MC68HC05V12 — Rev. 2.0
Pulse Width Modulators (PWMs)
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Technical Data