MC68HC908MR8 Datasheet, PDF (176/372 Pages) Motorola, Inc – Microcontrollers

Pulse-Width Modulator for Motor Control
NOTE: When PWMINT is cleared, pending CPU interrupts are inhibited.
PWMF— PWM Reload Flag
This read/write bit is set at the beginning of every reload cycle
regardless of the state of the LDOK bit. This bit is cleared by reading
PWM control register 1 with the PWMF flag set, then writing a logic 0
to PWMF. If another reload occurs before the clearing sequence is
complete, then writing logic 0 to PWMF has no effect.
1 = New reload cycle began.
0 = New reload cycle has not begun.
NOTE: When PWMF is cleared, pending PWM CPU interrupts are cleared
(excluding fault interrupts).
CAUTION:
Bits 2 and/or 3 of PCTL1 are reserved and must never be set to a 1.
Setting these bits to a 1 will affect the active PWM value registers.
Undesirable results will occur.
LDOK— Load OK Bit
This read/write bit allows the counter modulus, counter prescaler, and
PWM values in the buffered registers to be used by the PWM
generator. These values will not be used until the LDOK bit is set and
a new PWM load cycle begins. LDOK may be cleared, if it is set, by
writing a logic 0 to it prior to the beginning of a new PWM load cycle.
Internally this bit is automatically cleared after the new values are
loaded.
1 = Okay to load new modulus, prescaler, and PWM values at
beginning of next PWM load cycle
0 = Not okay to load new modulus, prescaler, and PWM values
NOTE: The user should initialize the PWM registers and set the LDOK bit before
enabling the PWM.
PWMEN — PWM Module Enable Bit
This read/write bit enables and disables the PWM generator and the
PWM pins. When PWMEN is clear, the PWM generator is disabled
and the PWM pins are in the high-impedance state (unless
OUTCTL = 1). When the PWMEN bit is set, the PWM generator and
PWM pins are activated. For more information, see 9.8 Initialization
and the PWMEN Bit.
1 = PWM generator and PWM pins enabled
0 = PWM generator and PWM pins disabled
Technical Data
176
MC68HC908MR8 — Rev 4.1
Pulse-Width Modulator for Motor Control (PWMMC) Freescale Semiconductor