MATLAB: Does the C24x PWM block’s documentation refers to the “Pulse Width” setting when it should refer to the “Duty Cycle” setting in Embedded Target for TI C2000

duty cycleelectric_motor_controlpower_conversion_controlpower_electronics_controlTarget Support Package TC2

In the C24x PWM block's documentation page the term "Pulse Width" should be replaced by "Duty Cycle".

Best Answer

This is an error within the documentation for Embedded Target for TI C2000 within the C24x PWM block's section.

The documentation should read as follows:

The value set in Duty Cycle above determines the value in the register.

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MATLAB: How to set up “Emulation Mode Bits” for the TC2 ePWM block in Target Support Package TC2 3.1 (R2008b)

The functionality to set ‘Emulation Mode Bits’ is not available for the TC2 ePWM block in Target Support Package TC2 3.1 (R2008b). These bits are kept as default "00" .

To work around this issue you can change those bits manually in the generated code via

 EPwmRegs->TBCTL.bit.FREE_SOFT

For example, consider running ‘c2808adcpwmasynctest’ demo. Generate the code for the model in the demo. Then, in Code Composer Studio you will find the file ‘c2808adcpwmasynctest.c’. In this file, there is a function "config_ePWMRegs" (or one with a similar name). Inside this function you will find the line which is setting CTRMODE bits:

 EPwmRegs->TBCTL.bit.CTRMODE = EPwmParams->TBCTL_CTRMODE;

Similarly, you may add the following line to change the FREE SOFT bits:

 EPwmRegs->TBCTL.bit.FREE_SOFT=  1x ;

MATLAB: How to set the duty cycle of the PWM channel for the DM6816 PWM block in xPC Target 2.7.2 (R14SP2)

We have verified that documentation for the Real Time Devices DM6816 PWM block found within the xPC Target I/O Block Reference section is incomplete as of xPC Target 2.7.2 (R14SP2). Here is some additional information related to setting the duty cycle of the PWM channel associated with that block:

The value of the duty cycle relies on the input to the block. Valid input to the DM6816 PWM block is a number in the range from 0 to 255. This input corresponds to the block duty cycle, where 0 is a duty cycle of 0% and 256 is 100%. Consequently, the maximum input duty cycle is:

255 / 256 = 0.996

To set a duty cycle of 0.06 for example, the block input associated with the PWM channel should be:

0.06 * 256 = 15.36

However, note that the block rounds to the nearest integer. As a result, the duty cycle is actually:

15 / 256 = 0.0586

Best Answer

Related Solutions

MATLAB: How to set up “Emulation Mode Bits” for the TC2 ePWM block in Target Support Package TC2 3.1 (R2008b)

MATLAB: How to set the duty cycle of the PWM channel for the DM6816 PWM block in xPC Target 2.7.2 (R14SP2)

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