Sync signals are precise time controlled signals
and are able to trigger time synchronized actions of the MainDevice. CPU core and DMA engine triggers are configured
independently for every end point. The following sections describe ESC signal
integration and various control triggers in the device.
- SYNC0: SYNC0 is the primary trigger and
can be generated in either a cyclic (periodic event generation like rise edge at
every x period) or one-shot mode. Furthermore, these modes can be either with or
without acknowledge, such that when enabled with acknowledge mode, the next
event is not generated until the acknowledgment is received from the controlling
MainDevice. If the
acknowledgment is delayed, the event is skipped and the next periodic event is
generated. Remember that the acknowledgment can be part of the interrupt
servicing from the PDI and such a delay in triggering the next event is
acceptable since the servicing routine can accordingly take action for the
period elapsed. These modes are shown in Figure 26-14.
- SYNC1: The SYNC1 generation follows the
SYNC0 generation with a programmable delay and depending upon the delay time
defined, SYNC1 can or cannot generate the pulse since the predefined delay from
the SYNC0 event is newly measured only after the SYNC1 event (except for the
start).
Note: - The SYNC0/1 when used in a system clock domain is
stretched to at least 3 clock-wide pulse.
- When ESC goes through a reset, the SYNC outputs
triggering external device events need to be kept at a safe value. At reset,
the output values are 0 and this can be an active state when the reset
occurs; therefore, the corresponding care of usage from the remote device
must be taken.