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PWM-Chopper (PC) Submodule

2.6.4.1One-Shot Pulse

The width of the first pulse can be programmed to any of 16 possible pulse width values. The width or period of the first pulse is given by:

T1stpulse = TSYSCLKOUT × 8 × OSHTWTH

Where TSYSCLKOUT is the period of the system clock (SYSCLKOUT) and OSHTWTH is the four control bits (value from 1 to 16)

Figure 2-33shows the first and subsequent sustaining pulses and Table 7.3 gives the possible pulse width values for a SYSCLKOUT = 100 MHz.

Figure 2-33. PWM-Chopper Submodule Waveforms Showing the First Pulse and Subsequent Sustaining

Pulses

Start OSHT pulse

EPWMxA in

PSCLK

Prog. pulse width (OSHTWTH)

OSHT

EPWMxA out

Sustaining pulses

Table 2-16. Possible Pulse Width Values for

SYSCLKOUT = 100 MHz

OSHTWTHz

Pulse Width

(hex)

(nS)

0

80

1

160

2

240

3

320

4

400

5

480

6

560

7

640

8

720

9

800

A

880

B

960

C

1040

D

1120

E

1200

F

1280

SPRU791D–November 2004–Revised October 2007

ePWM Submodules

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Texas Instruments 28xxx, TMS320x28xx manual One-Shot Pulse, Possible Pulse Width Values for Sysclkout = 100 MHz, OSHTWTHz