TMS320F2809, TMS320F2808, TMS320F2806
TMS320F2802, TMS320F2801, UCD9501
TMS320C2802, TMS320C2801, and TMS320F2801x DSPs
www.ti.com
SPRS230H–OCTOBER 2003–REVISED JUNE 2006
Time−base (TB)
Sync
CTR=ZERO
CTR=CMPB
Disabled
in/out
select
Mux
TBPRD shadow (16)
TBPRD active (16)
EPWMxSYNCO
EPWMxSYNCI
CTR=PRD
TBCTL[SYNCOSEL]
TBCTL[CNTLDE]
Counter
up/down
(16 bit)
TBCTL[SWFSYNC]
(software forced sync)
CTR=ZERO
CTR_Dir
TBCNT
active (16)
TBPHSHR (8)
16
8
CTR = PRD
CTR = ZERO
CTR = CMPA
CTR = CMPB
CTR_Dir
Phase
Event
trigger
and
interrupt
(ET)
EPWMxINT
TBPHS active (24)
control
EPWMxSOCA
EPWMxSOCB
Counter compare (CC)
CTR=CMPA
CMPAHR (8)
Action
qualifier
(AQ)
16
8
HiRes PWM (HRPWM)
CMPA active (24)
EPWMA
EPWMB
EPWMxAO
CMPA shadow (24)
CTR=CMPB
Dead
band
(DB)
PWM
chopper
(PC)
Trip
zone
(TZ)
16
EPWMxBO
EPWMxTZINT
TZ1 to TZ6
CMPB active (16)
CMPB shadow (16)
CTR = ZERO
Figure 4-4. ePWM Sub-Modules Showing Critical Internal Signal Interconnections
4.3 Hi-Resolution PWM (HRPWM)
The HRPWM module offers PWM resolution (time granularity) which is significantly better than what can
be achieved using conventionally derived digital PWM methods. The key points for the HRPWM module
are:
•
•
Significantly extends the time resolution capabilities of conventionally derived digital PWM
Typically used when effective PWM resolution falls below ~ 9-10 bits. This occurs at PWM frequencies
greater than ~200 KHz when using a CPU/System clock of 100 MHz.
•
•
This capability can be utilized in both duty cycle and phase-shift control methods.
Finer time granularity control or edge positioning is controlled via extensions to the Compare A and
Phase registers of the ePWM module.
•
HRPWM capabilities are offered only on the A signal path of an ePWM module (i.e., on the EPWMxA
output). EPWMxB output has conventional PWM capabilities.
NOTE
Only PWM channels ePWM 1A, 2A, 3A, 4A support HRPWM features. The remaining
ePWM channels do not support the HRPWM features.
Peripherals
55
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