Capture And Apwm Modes Of Operation - Texas Instruments Concerto F28M35 Series Technical Reference Manual

Capture and APWM Operating Mode
8.3 Capture and APWM Operating Mode
You can use the eCAP module resources to implement a single-channel PWM generator (with 32 bit
capabilities) when it is not being used for input captures. The counter operates in count-up mode,
providing a time-base for asymmetrical pulse width modulation (PWM) waveforms. The CAP1 and CAP2
registers become the active period and compare registers, respectively, while CAP3 and CAP4 registers
become the period and capture shadow registers, respectively.
capture and auxiliary pulse-width modulator (APWM) modes of operation.
SyncIn
ECAPxINT
SyncIn
Syncout
ECAPxINT
A A single pin is shared between CAP and APWM functions. In capture mode, it is an input; in APWM mode, it is an
output.
B In APWM mode, writing any value to CAP1/CAP2 active registers also writes the same value to the corresponding
shadow registers CAP3/CAP4. This emulates immediate mode. Writing to the shadow registers CAP3/CAP4 invokes
the shadow mode.
Figure 8-2 further descries the output of the eCAP in APWM mode based on the CMP and PRD values.
792
C28 Enhanced Capture (eCAP) Module
Figure 8-1. Capture and APWM Modes of Operation
Counter ("timer")
32
CAP1 reg
CAP2 reg
CAP3 reg
CAP4 reg
Interrupt I/F
Or
Counter ("timer")
32
Period reg
(active) ("CAP1")
Compare reg
(active) ("CAP2")
Period reg
(shadow) ("CAP3")
Compare reg
(shadow) ("CAP4")
Interrupt I/F
Copyright © 2012–2019, Texas Instruments Incorporated
Figure 8-1 is a high-level view of both the
Capture
mode
depends on
Sequencing
Edge detection
Edge polarity
Prescale
APWM
mode
PWM
Compare logic
SPRUH22I – April 2012 – Revised November 2019
Submit Documentation Feedback
www.ti.com
Note:
Same pin
operating
mode
ECAPx
pin
APWMx
pin