BECKHOFF EtherCAT Technology Section I - Manual (Page 102)

Interrupts
I-82 Slave Controller – Technology
12 Interrupts
ESCs support two types of interrupts: AL Event Requests targeted at a µController, and ECAT event
requests targeted at the EtherCAT master. Additionally, the Distributed Clocks SyncSignals can be
used as interrupts for a µController as well.
12.1 AL Event Request (PDI Interrupt)
AL Event Requests can be signaled to a µController using the PDI Interrupt Request signal
(IRQ/SPI_IRQ, etc.). For IRQ generation, the AL Event Request register (0x0220:0x0223) is combined
with the AL Event Mask register (0x0204:0x0207) using a logical AND operation, then all resulting bits
are combined (logical OR) into one interrupt signal. The output driver characteristics of the IRQ signal
are configurable using the SYNC/LATCH PDI configuration register (0x0151). The AL Event Mask
register allows for selecting the interrupts which are relevant for the µController and handled by the
application.
EtherCAT Device
µController
IRQ
SYNC0
SYNC1
IRQ_A
IRQ_B
IRQ_C
DC
SYNC1
SYNC0
32 32
32
32
& ≥1
2
3
&
&
8
3
7
AL Event
Request
Register
(0x0220:0x0223)
AL Event
Mask
Register
(0x0204:0x0207)
SYNC/Latch
PDI Config.
Register
(0x0151)
Other
Interrupt
sources
Figure 41: PDI Interrupt Masking and interrupt signals
The DC SyncSignals can be used for interrupt generation in two ways:

The DC SYNC signals are mapped into the AL Event Request Register (configured with
SYNC/LATCH PDI Configuration register 0x0151.3/7). In this case, all interrupts from the ESC to
the µController are combined into one IRQ signal, and the Distributed Clocks LATCH0/1 inputs
can still be used. The IRQ signal has a jitter of ~40 ns.

The DC SyncSignals are directly connected to µController interrupt inputs. The µController can
react on DC SyncSignal interrupts faster (without reading AL Request register), but it needs more
interrupt inputs. The jitter of the SyncSignals is ~12 ns. The DC Latch functions are only available
for one Latch input or not at all (if both DC SYNC outputs are used).
Registers used for AL event requests are described in Table 47:
Table 47: Registers for AL Event Request Configuration
Register Address Name Description
0x0150 PDI Configuration IRQ driver characteristics, depending on
PDI
0x0151 SYNC/LATCH PDI Configuration Mapping DC SyncSignals to Interrupts
0x0204:0x0207 AL Event Mask Mask register
0x0220:0x0223 AL Event Request Pending Interrupts
0x0804 + N*8 SyncManager Control Mapping SyncManager Interrupts
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.