Shorten dshot pulse width #20379
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Shorten dshot pulse width #20379
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IamPete1
reviewed
Mar 25, 2022
…re accurate prescaler calculation
andyp1per
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Flight tested on a 3" miniquad (Tekko32 ESCs). Arming tested on a 7" (T-Motor F55 Pro II). Neopixel tested on a 7". All worked fine. |
tridge
approved these changes
Mar 30, 2022
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@andyp1per, did you say that you wanted this included in 4.2 as well? |
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@rmackay9 yes - but only once its had a few more people flying it |
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It is possible to construct valid dshot and neopixel packets using fewer DMA beats. This allows more accurate frequency resolution because a lower frequency is required and the prescaler needed to divide up the system clock frequency can be higher. In testing this allowed ArduCopter to successfully drive BlueJay 0.14 ESCs from an omnibusf4pro-bdshot whereas with the current code the frequency difference is too large and the BlueJay firmware does not recognize the dshot signal.
This shortens the dshot pulse to 8 ticks with 3/8 for 0 and 6/8 for 1
This shortens the neopixel pulse to 11 ticks with 4/11 for 0 and 9/11 for 1
This appears to allow BlueJay ESCs to work with ArduPilot which are quite timing sensitive