6.3 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 compare
shadow registers, respectively.
is a high-level view of both the capture and auxiliary pulse-width
modulator (APWM) modes of operation.
further descries the output of the eCAP in APWM mode based on the CMP and PRD values.
Counter (”timer”)
SyncIn
32
CAP1 reg
CAP2 reg
CAP4 reg
CAP3 reg
Interrupt I/F
ECAPxINT
Sequencing
Edge detection
Edge polarity
Prescale
ECAPx
pin
Note:
Same pin
depends on
operating
mode
Counter (”timer”)
SyncIn
32
Capture
mode
APWM
mode
Period reg
(active) (”CAP1”)
Compare reg
(active) (”CAP2”)
Period reg
(shadow) (”CAP3”)
(shadow) (”CAP4”)
Compare reg
Interrupt I/F
ECAPxINT
PWM
Compare logic
APWMx
pin
Or
Syncout
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 6-2. Capture and APWM Modes of Operation
Enhanced Capture (eCAP)
432
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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