MC68336/376
REGISTER SUMMARY
MOTOROLA
USER’S MANUAL
Rev. 15 Oct 2000
D-67
write a zero to the bit. Writing a one to FLAG has no effect. When the PWM is disabled,
FLAG remains cleared.
When the interrupt level set specified by IL[2:0] is non-zero, an interrupt request is
generated when the FLAG bit is set.
IL[2:0] — Interrupt Level Field
When the PWMSM generates an interrupt request, IL[2:0] determines which of the
interrupt request signals is asserted. When a request is acknowledged, the CTM4
compares IL[2:0] to a mask value supplied by the CPU32 to determine whether to
respond. IL[2:0] must have a value in the range of $0 (interrupts disabled) to $7
(highest priority).
IARB3 — Interrupt Arbitration Bit 3
This bit and the IARB[2:0] field in BIUMCR are concatenated to determine the interrupt
arbitration number for the submodule requesting interrupt service. Refer to D.7.1 BIU PIN — Output Pin Status
This status bit indicates the logic state present on the PWM output pin.
0 = Logic zero present on the PWM output pin.
1 = Logic one present on the PWM output pin.
PIN is a read-only bit; writing to it has no effect.
LOAD — Period and Pulse Width Register Load Control
Setting LOAD reinitializes the PWMSM and starts a new PWM period without causing
a glitch on the output signal.
0 = No action
1 = Load period and pulse width registers
This bit is always read as a zero. Writing a one to this bit results in the following imme-
diate actions:
The contents of PWMA1 (period value) are transferred to PWMA2.
The contents of PWMB1 (pulse width value) are transferred to PWMB2.
The counter register (PWMC) is initialized to $0001.
The control logic and state sequencer are reset.
The FLAG bit is set.
The output flip-flop is set if the new value in PWMB2 is not $0000.
NOTE
Writing a one to the LOAD bit when the EN bit = 0, (when the
PWMSM is disabled), has no effect.
POL — Output Pin Polarity Control
This control bit sets the polarity of the PWM output signal. It works in conjunction with
the EN bit and controls whether the PWMSM drives the output pin with the non-
inverted or inverted state of the output flip-flop. Refer to Table D-49.