LAUNCHXL-F28379D: What does DAC 1-4 mean?

Junfei Tang

Part Number: LAUNCHXL-F28379D
Other Parts Discussed in Thread: TMS320F28379D,

Hi,

I see that there are DAC Modules A, B and C in the datasheet of TMS320F28379D. However, apart from the ABC input pins, I find 4 additional pins in the datasheet of LAUNCHXL-F28379D, which are DAC1, 2, 3 and 4. I am wondering how are these four pins used because I cannot find the corresponding pins in the datasheet of TMS320F28379D.

Thanks!

Junfei Tang

over 7 years ago

0 Richard Poley over 7 years ago

TI__Mastermind 27200 points

Hi Junfei,

The LaunchPad board has four low-pass RC filters, each connected to a different PWM output on the device. If you look on p.5 of the board schematics you'll see them. The idea is you filter out the switching frequency to leave a duty cycle modulated DC output - a sort of pseudo-DAC. These are numbered DAC1-4 on the board.

Regards,

Richard

0 Junfei Tang over 7 years ago in reply to Richard Poley

Intellectual 315 points

Hi,

OK, now I understand. This is a quite brilliant implementation. I was confused for a long time. Thanks for the explanation!

Sincerely,

Junfei Tang

0 Junfei Tang over 7 years ago in reply to Richard Poley

Intellectual 315 points

Thanks for the explanation!

By the way, I guess it would be better to write "PWM-Based-DAC" on the schematic instead of "PWM/Based/DAC". I previously read the schematic and "PWM/Based/DAC" made me believe that there is a pin on the TMS320F28379D chip which can give PWM or DAC or a signal called "based"...

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LAUNCHXL-F28379D: What does DAC 1-4 mean?