contains a code sample showing initialization and run time for the waveforms in
TBCTR
EPWMxA
EPWMxB
TBPRD
value
CA
Z
P
CB
Z
P
CB
CA
Z
P
Z
P
CA
Z
P
CA
Z
P
CB
CB
A.
PWM period = (TBPRD + 1 ) × T
TBCLK
B.
Duty modulation for EPWMxA is set by CMPA, and is active high (that is, high time duty proportional to CMPA).
C.
Duty modulation for EPWMxB is set by CMPB and is active high (that is, high time duty proportional to CMPB).
D.
The "Do Nothing" actions ( X ) are shown for completeness, but will not be shown on subsequent diagrams.
E.
Actions at zero and period, although appearing to occur concurrently, are actually separated by one TBCLK period. TBCTR wraps from
period to 0000.
Figure 3-22. Up, Single Edge Asymmetric Waveform, With Independent Modulation on EPWMxA and
EPWMxB—Active High
// Initialization Time
// = = = = = = = = = = = = = = = = = = = = = = = =
EPwm1Regs.TBPRD = 600; // Period = 601 TBCLK counts
EPwm1Regs.CMPA.half.CMPA = 350; // Compare A = 350 TBCLK counts
EPwm1Regs.CMPB = 200; // Compare B = 200 TBCLK counts
EPwm1Regs.TBPHS = 0; // Set Phase register to zero
EPwm1Regs.TBCTR = 0; // clear TB counter
EPwm1Regs.TBCTL.bit.CTRMODE = TB_COUNT_UP;
EPwm1Regs.TBCTL.bit.PHSEN = TB_DISABLE; // Phase loading disabled
EPwm1Regs.TBCTL.bit.PRDLD = TB_SHADOW;
EPwm1Regs.TBCTL.bit.SYNCOSEL = TB_SYNC_DISABLE;
EPwm1Regs.TBCTL.bit.HSPCLKDIV = TB_DIV1; // TBCLK = SYSCLK
EPwm1Regs.TBCTL.bit.CLKDIV = TB_DIV1;
EPwm1Regs.CMPCTL.bit.SHDWAMODE = CC_SHADOW;
EPwm1Regs.CMPCTL.bit.SHDWBMODE = CC_SHADOW;
EPwm1Regs.CMPCTL.bit.LOADAMODE = CC_CTR_ZERO; // load on CTR = Zero
EPwm1Regs.CMPCTL.bit.LOADBMODE = CC_CTR_ZERO; // load on CTR = Zero
EPwm1Regs.AQCTLA.bit.ZRO = AQ_SET;
EPwm1Regs.AQCTLA.bit.CAU = AQ_CLEAR;
EPwm1Regs.AQCTLB.bit.ZRO = AQ_SET;
EPwm1Regs.AQCTLB.bit.CBU = AQ_CLEAR;
//
// Run Time
// = = = = = = = = = = = = = = = = = = = = = = = =
EPwm1Regs.CMPA.half.CMPA = Duty1A; // adjust duty for output EPWM1A
EPwm1Regs.CMPB = Duty1B; // adjust duty for output EPWM1B
Enhanced Pulse Width Modulator (ePWM) Module
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
TMS320x2806x Microcontrollers
271
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
Страница 2: ......