BECKHOFF EtherCAT Technology Section I - Manual (Page 85)

Distributed Clocks
Slave Controller – Technology I-65
The registers used for LatchSignal event time stamping are shown in Table 34:
Table 34: Registers for Latch Input Events
Register Address Name Description
0x0141[3:2] ESC Configuration Enable/Disable DC Units (power saving)
0x0151 Sync/Latch PDI Configuration Configuration of SYNC/LATCH[1:0] pins
0x0980[5:4] Cyclic Unit Control Assignment of cyclic function to EtherCAT or
PDI
0x09A8 Latch0 Control Latch unit configuration for Latch0
0x09A9 Latch1 Control Latch unit configuration for Latch1
0x09AE Latch0 Status Latch status of Latch0
0x09AF Latch1 Status Latch status Latch1
0x09B0:0x09B7 Latch0 Time Positive Edge System time at positive edge Latch0
0x09B8:0x09BF Latch0 Time Negative Edge System time at negative edge Latch0
0x09C0:0x09C7 Latch1 Time Positive Edge System time at positive edge Latch1
0x09C8:0x09CF Latch1 Time Negative Edge System time at negative edge Latch1
0x09F0:0x09F3
EtherCAT Buffer Change
Event Time Local time at beginning of frame causing
ECAT SyncManager buffer change event
0x09F8:0x09FB PDI Buffer Start Event Time
Local time at PDI SyncManager buffer start
event
0x09FC:0x09FF
PDI Buffer Change Event
Time Local time at PDI SyncManager buffer
change event
NOTE: Some of these registers are set via SII EEPROM/IP Core configuration, or they are not available in
specific ESCs. Refer to Section II for details.
9.2.4.1 Single Event Mode
In single event mode, only the timestamps of the first rising and the first falling edge of the
LatchSignals are recorded. The Latch Status registers (0x09AE:0x09AF) contain information about the
events which already have occurred. The Latch Time registers (0x09B0 to 0x09CF) contain the time
stamps.
Each event is acknowledged by reading the corresponding Latch Time register. After reading the
Latch Time register, the Latch unit is waiting for the next event. Latch events are mapped to the AL
Event Request register in single event mode.
9.2.4.2 Continuous Mode
In continuous mode, each event is stored in the Latch Time registers. At reading, the time stamp of the
last event is read. The Latch Status registers (0x09AE:0x09AF) do not reflect the latch event states in
continuous mode.
9.2.4.3 SyncManager Event
Some ESCs support debugging of SyncManager interactions with time stamps for buffer events. The
last event can be read out at the SyncManager Event Time registers (0x09F0:0x09FF), if the
SyncManager is configured appropriately.
9.2.5 ECAT or PDI Control
The SyncSignal unit and the two LatchSignal units of the Distributed Clocks entity can be assigned
independently by the master to be controlled either by ECAT or a local µController (PDI) using the
Cyclic Unit Control register 0x0980. With PDI control, a µController can e.g. set up cyclic interrupts for
itself.