ePWM Submodules
701
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Enhanced Pulse Width Modulator (ePWM) Module
zone, event-trigger, and time-base submodules to:
–
generate a trip zone interrupt
–
generate an ADC start of conversion
–
force an event
–
generate a synchronization event for synchronizing the ePWM module TBCTR.
•
Event filtering (blanking window logic) can optionally blank the input signal to remove noise.
7.2.9.2
Enhanced Trip Action
In order to allow multiple comparators at a time to affect DCA/BEVTx events and trip actions, there is a
OR logic to bring together ALL trip inputs (up to 15) from sources external to the ePWM module and feed
into DCAH, DCAL, DCBH, and DCBL as “combinational input” using the DCTRIPSEL register. This is
configured by writing appropriate value [Trip Combination input ] to the
DCAHCOMPSEL,DCALCOMPSEL, DCBHCOMPSEL, DCBLCOMPSEL bit fields in the DCTRIPSEL
register.
The user has an discrete choice for which trip input to put through the combinational logic for Digital
Compare A High/Low (DCAH, DCAL) and Digital Compare B High/Low (DCBH, DCBL) signals generation.
This is acheived using the selection from DCAHTRIPSEL, DCALTRIPSEL, DCBHTRIPSEL and
DCBLTRIPSEL register. The approprite bit when set indicates that Trip input is chosen for “combinational
input” by the DCTRIPSEL register.
Apart from these options user can also make the external trip inputs which feed into the OR gate
individually selectable and not go through the “combinational input” by using the DCTRIPSEL register.
7.2.9.3
Controlling and Monitoring the Digital Compare Submodule
The digital compare submodule operation is controlled and monitored through the following registers:
(1)
These registers are EALLOW protected and can be modified only after executing the EALLOW instruction. For more information,
see the device-specific version of the System Control and Interrupts Reference Guide.
(2)
The TZDCSEL register is part of the trip-zone submodule but is mentioned again here because of its functional significance to
the digital compare submodule.
Table 7-24. Digital Compare Submodule Registers
Register Name
Address Offset
Shadowed
Description
TZDCSEL
(1) (2)
0x13
No
Trip Zone Digital Compare Select Register
DCTRIPSEL
(1)
0x30
No
Digital Compare Trip Select Register
DCACTL
(1)
0x31
No
Digital Compare A Control Register
DCBCTL
(1)
0x32
No
Digital Compare B Control Register
DCFCTL
(1)
0x33
No
Digital Compare Filter Control Register
DCCAPCTL
(1)
0x34
No
Digital Compare Capture Control Register
DCFOFFSET
0x35
Writes
Digital Compare Filter Offset Register
DCFOFFSETCNT
0x36
No
Digital Compare Filter Offset Counter Register
DCFWINDOW
0x37
No
Digital Compare Filter Window Register
DCFWINDOWCNT
0x38
No
Digital Compare Filter Window Counter Register
DCCAP
0x39
Yes
Digital Compare Counter Capture Register
DCAHTRIPSEL
0x4C
No
Digital Compare AH Trip Select
DCALTRIPSEL
0x4D
No
Digital Compare AL Trip Select
DCBHTRIPSEL
0x4E
No
Digital Compare BH Trip Select
DCBLTRIPSEL
0x4F
No
Digital Compare BL Trip Select