Event Processing and EDMA Control Registers
6-6
6.3
Event Processing and EDMA Control Registers
Each of the 16 channels in the EDMA have specific events associated with
them. These events trigger the data transfer associated with that channel. The
list of control registers that perform various processing of events is shown in
Table 6–1.
An event is signaled to the EDMA controller by way of a low-to-high transition
on one of its 16 event inputs. All events are captured in the event register (ER),
even when the events are disabled. The 32-bit ER shown in Figure 6–3 con-
tains one bit for each event, or a total of 16 bits. Section 6.7.1 describes the
type of synchronization events and the EDMA channels associated with each
of them.
Table 6–1. EDMA Control Registers
Byte
Address
Acronym
Register Name
Section
01A0 FFE0h
PQSR
Priority queue status register
6.14
01A0 FFE4h
CIPR
Channel interrupt pending register
6.13
01A0 FFE8h
CIER
Channel interrupt enable register
6.13
01A0 FFECh
CCER
Channel chain enable register
6.13.2
01A0 FFF0h
ER
Event register
6.3
01A0 FFF4h
EER
Event enable register
6.3
01A0 FFF8h
ECR
Event clear register
6.3
01A0 FFFCh
ESR
Event set register
6.3
In addition to the event register, the EDMA controller also provides the user
the option of enabling/disabling events. Any of the 16 event bits in the 32-bit
event enable register (EER) shown in Figure 6–4 can be set to ‘1’ to enable
that event. Note that all events that are captured by the EDMA are latched in
the ER even if that event is disabled. This is analogous to an interrupt enable
and interrupt-pending register for interrupt processing. This ensures that no
events are dropped by the EDMA. Thus, re-enabling an event with a pending
event signaled in the ER forces the EDMA controller to process that event ac-
cording to its priority. Writing a ‘0’ to the corresponding bit in the EER disables
an event.