Analog Devices ADSP-BF506F Hardware Reference Manual page 551

latency and jitter from the external sync pulse to the actual PWM outputs.
If the same asynchronous external sync pulse is received by two indepen-
dent PWM Controllers, synchronization of
independently and the jitter between the PWM Controllers will not be in
unison. The size of the sync pulse on
system clock periods.
The produced PWM output signals can be shut off via:
• Hardware. A dedicated asynchronous PWM shutdown pin
(
PWM_TRIP
the
PWMTRIP_DSBL
places all six PWM outputs in the "off" state (as determined by the
state of the
ware shutdown mechanism is asynchronous so that the associated
PWM disable circuitry does not go through any clocked logic,
thereby ensuring correct PWM shutdown even in the event of a
loss of the processor system clock. A trip shutdown in hardware
resets the
grammable registers maintain their current state.
• Software. The PWM system may be shut down in software by
disabling the

On many processors, the PWM pins are multiplexed with other
functionality. Because they can be in a high-impedance state before
the
PORTx_MUX
tionality, there should be external pull-down logic for the
pin in these cases. For these and other questions about pin multi-
plexing, see ADSP-BF504, ADSP-BF504F, ADSP-BF506F
Embedded Processor Data Sheet.
The PWM unit is capable of generating two different interrupt types. One
interrupt (
PWM_SYNCINT
the pulse, which is internally generated. The other interrupt
PWM_SYNC
( ) is generated on the occurrence of
PWM_TRIPINT
ADSP-BF50x Blackfin Processor Hardware Reference
) that when brought low (provided it is not disabled by
bit of the
bit of the
PWM_POLARITY
bit in the
PWM_EN PWM_CTRL
bit in the
PWM_ENABLE
registers are programmed to select the PWM func-
) is generated on the occurrence of a rising edge on
PWM_SYNC
must be greater than two
PWM_SYNC
register) instantaneously
PWM_CTRL
register). This hard-
PWM_CTRL
register, but all the other pro-
register.
PWM_CTRL
PWM_TRIP
PWM Controller
is also done
PWM_TRIP
, the PWM
14-7