TMS320F2809_08 Datasheet, PDF (58/140 Pages) Texas Instruments – Digital Signal Processors

TMS320F2809, TMS320F2808, TMS320F2806
TMS320F2802, TMS320F2801
TMS320C2802, TMS320C2801, and TMS320F2801x DSPs
SPRS230J – OCTOBER 2003 – REVISED SEPTEMBER 2007
Time−base (TB)
TBPRD shadow (16)
TBPRD active (16)
CTR=ZERO
CTR=CMPB
Disabled
Sync
in/out
select
Mux
CTR=PRD
TBCTL[CNTLDE]
Counter
up/down
(16 bit)
TBCNT
active (16)
CTR=ZERO
CTR_Dir
16
TBPHSHR (8)
8
TBPHS active (24)
Phase
control
Counter compare (CC)
CTR=CMPA
CMPAHR (8)
16
8
CMPA active (24)
CMPA shadow (24)
Action
qualifier
(AQ)
EPWMA
TBCTL[SYNCOSEL]
TBCTL[SWFSYNC]
(software forced sync)
CTR = PRD
CTR = ZERO
CTR = CMPA
CTR = CMPB
CTR_Dir
Event
trigger
and
interrupt
(ET)
HiRes PWM (HRPWM)
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EPWMxSYNCO
EPWMxSYNCI
EPWMxINT
EPWMxSOCA
EPWMxSOCB
EPWMxAO
CTR=CMPB
16
CMPB active (16)
CMPB shadow (16)
EPWMB
Dead
band
(DB)
PWM
chopper
(PC)
CTR = ZERO
Trip
zone
(TZ)
EPWMxBO
EPWMxTZINT
TZ1 to TZ6
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.
4.4 Enhanced CAP Modules (eCAP1/2/3/4)
The 280x device contains up to four enhanced capture (eCAP) modules. Figure 4-5 shows a functional
block diagram of a module. See the TMS320x280x Enhanced Capture (eCAP) Module Reference Guide
(literature number SPRU807) for more details.
The eCAP modules are clocked at the SYSCLKOUT rate.
58
Peripherals
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