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Karen Darnell

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About Karen Darnell

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  1. PWMs on TI boards are daisy chained. This daisy chaining cannot be adjusted using Embed. Daisy chained PWMs on the F280049 board (which has eight PWMs): PWM unit 1 is a lead unit with PWMs 2 and 3 daisy chained. PWM unit 4 is a lead unit with PWMs 5 and 6 daisy chained. PWM unit 7 is a lead unit with PWM 8 daisy chained. For a lead, it should not be relative to anything (this unit can take an external input through a GPIO to trigger it). Daisy chained units can have a phase shift relative to the previous unit (TBPHS). For example, unit 2 is phase shifted with respect to unit 1; unit 3 is phase shifted with respect to unit 2. You want unit 1 and unit 4 to be 180 deg out of phase, but because of the way daisy chaining works, this is not possible unless unit 4 is reassigned to unit 2. Then it can be phase shifted 180 deg.
  2. The synch-in signal to the first unit is a GPIO pin, but you don't have to use it. Just don't check the "TBCTR=TBPHS on the SYNCHI Pulse." The first PWM can use its internal counter and subsequent units can sync in a daisy-chained-way to it. Additionally, you do not have to connect the synout pin to syncin GPIO pin through the hardware. The connection is internal between consecutive triples of PWM units. So unit 1 -> unit 2 -> unit 3, and unit 4 -> unit 5-> unit 6, etc.
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