#include "modules/actuators/dshot_erps.h"

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Functions
static uint8_t	crc4 (uint16_t val)
	calculate crc4 More...

static DshotEPeriodPacket	eperiodToPacked (const uint32_t eperiod)
	encode packet from eperiod More...

static uint32_t	greyEncode (uint32_t num)
	get grey binary value from natural binary More...

static uint32_t	greyDecode (const uint32_t num)
	get natural binary value from grey binary More...

static uint32_t	gcrEncode (uint32_t from)
	encode 16 bit value to 20 bits GCR More...

static uint32_t	gcrDecode (uint32_t from)
	decode 20 bits GCR value to 16 bits natural More...

static uint32_t	eperiodEncode (const uint16_t eperiod)
	encode eperiod to 20 bits GCR of grey value More...

static uint32_t	eperiodDecode (const uint32_t frame)
	decode 20 bits GCR of grey value to eperiod More...

static void	setFromEperiod (DshotErps *derpsp, uint32_t eperiod)
	initialize from eperiod in microseconds More...

static void	frameToPacket (DshotErps *derpsp)
	decode eperiod More...

static void	packetToFrame (DshotErps *derpsp)
	encode eperiod More...

const DshotErps *	DshotErpsSetFromFrame (DshotErps *derpsp, uint32_t frame)
	initialise from GCR encoded frame More...

const DshotErps *	DshotErpsSetFromRpm (DshotErps *derpsp, uint32_t rpm)
	initialise from rpm value More...

uint32_t	DshotErpsGetEperiod (const DshotErps *derpsp)
	return eperiod from mantisse and exponent More...

uint32_t	DshotErpsGetRpm (const DshotErps *derpsp)
	calculate and return rpm More...

bool	DshotErpsCheckCrc4 (const DshotErps *derpsp)
	check packed validity More...

Variables
static const uint8_t	gcrNibble [16]
	IBM GCR encoding lookup table. More...

static const uint8_t	gcrNibbleInv [32]
	IBM GCR decoding lookup table. More...

Function Documentation

◆ crc4()

static uint8_t crc4 ( uint16_t val )

static

calculate crc4

Parameters

[in] val

Returns: true if CRC is OK

Definition at line 111 of file dshot_erps.c.

References val.

Referenced by DshotErpsCheckCrc4(), and eperiodToPacked().

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◆ DshotErpsCheckCrc4()

bool DshotErpsCheckCrc4 ( const DshotErps * derpsp )

check packed validity

Parameters

[in] derpsp pointer to the DshotErps object

Returns: true if CRC is OK @api

Definition at line 99 of file dshot_erps.c.

References crc4(), DshotErps::ep, and DshotEPeriodPacket::rawFrame.

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◆ DshotErpsGetEperiod()

uint32_t DshotErpsGetEperiod ( const DshotErps * derpsp )

private

return eperiod from mantisse and exponent

Parameters

[in] derpsp pointer to the DshotErps object

Returns: eperiod in microseconds

Note: getEperiod avoid a division and is more cpu friendly than getRpm

Definition at line 72 of file dshot_erps.c.

References DshotErps::ep.

Referenced by DshotErpsGetRpm().

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◆ DshotErpsGetRpm()

uint32_t DshotErpsGetRpm ( const DshotErps * derpsp )

calculate and return rpm

Parameters

[in] derpsp pointer to the DshotErps object

Returns: rotational speed in RPM

Note: involve a division, which is a cpu cycle hog, If you can use getEperiod instead, it will be less calculus intensive @api

Definition at line 87 of file dshot_erps.c.

References DshotErpsGetEperiod().

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◆ DshotErpsSetFromFrame()

const DshotErps* DshotErpsSetFromFrame	(	DshotErps *	derpsp,
		uint32_t	frame
	)

initialise from GCR encoded frame

Parameters

[in] derpsp pointer to the DshotErps object @api

Definition at line 44 of file dshot_erps.c.

References DshotErps::ef, frame, and frameToPacket().

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◆ DshotErpsSetFromRpm()

const DshotErps* DshotErpsSetFromRpm	(	DshotErps *	derpsp,
		uint32_t	rpm
	)

initialise from rpm value

Parameters

[in] derpsp pointer to the DshotErps object @api

Definition at line 57 of file dshot_erps.c.

References rpm, and setFromEperiod().

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◆ eperiodDecode()

static uint32_t eperiodDecode ( const uint32_t frame )

static

decode 20 bits GCR of grey value to eperiod

Parameters

[in] GCR(0,2) encoded value received from ESC

Returns: eperiod in microseconds

Definition at line 230 of file dshot_erps.c.

References frame, gcrDecode(), and greyDecode().

Referenced by frameToPacket().

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◆ eperiodEncode()

static uint32_t eperiodEncode ( const uint16_t eperiod )

static

encode eperiod to 20 bits GCR of grey value

Parameters

[in] eperiod in microseconds

Returns: GCR(0,2) encoded value ready to be transmitted

Definition at line 218 of file dshot_erps.c.

References gcrEncode(), and greyEncode().

Referenced by packetToFrame().

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◆ eperiodToPacked()

static DshotEPeriodPacket eperiodToPacked ( const uint32_t eperiod )

static

encode packet from eperiod

Parameters

[in] eperiod in microseconds

Returns: encoded DshotEPeriodPacket

Definition at line 124 of file dshot_erps.c.

References crc4(), and p.

Referenced by setFromEperiod().

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◆ frameToPacket()

static void frameToPacket ( DshotErps * derpsp )

static

decode eperiod

Parameters

[in,out] derpsp pointer to the DshotErps object

Definition at line 254 of file dshot_erps.c.

References DshotErps::ef, DshotErps::ep, eperiodDecode(), and DshotEPeriodPacket::rawFrame.

Referenced by DshotErpsSetFromFrame().

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◆ gcrDecode()

static uint32_t gcrDecode ( uint32_t from )

static

decode 20 bits GCR value to 16 bits natural

Parameters

[in] GCR(0,2) encoded value

Returns: binary value

Definition at line 194 of file dshot_erps.c.

References gcrNibbleInv.

Referenced by eperiodDecode().

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◆ gcrEncode()

static uint32_t gcrEncode ( uint32_t from )

static

encode 16 bit value to 20 bits GCR

Parameters

[in] binary value

Returns: GCR(0,2) encoded value

Definition at line 175 of file dshot_erps.c.

References gcrNibble.

Referenced by eperiodEncode().

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◆ greyDecode()

static uint32_t greyDecode ( const uint32_t num )

static

get natural binary value from grey binary

Parameters

[in] grey encoded value

Returns: num natural binary value

Definition at line 163 of file dshot_erps.c.

Referenced by eperiodDecode().

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◆ greyEncode()

static uint32_t greyEncode ( uint32_t num )

static

get grey binary value from natural binary

Parameters

[in] num natural binary value

Returns: grey encoded value

Definition at line 146 of file dshot_erps.c.

Referenced by eperiodEncode().

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◆ packetToFrame()

static void packetToFrame ( DshotErps * derpsp )

static

encode eperiod

Parameters

[in,out] derpsp pointer to the DshotErps object

Definition at line 266 of file dshot_erps.c.

References DshotErps::ef, DshotErps::ep, eperiodEncode(), and DshotEPeriodPacket::rawFrame.

Referenced by setFromEperiod().

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◆ setFromEperiod()

static void setFromEperiod	(	DshotErps *	derpsp,
		uint32_t	eperiod
	)

static

initialize from eperiod in microseconds

Parameters

[in]	derpsp	pointer to the `DshotErps` object
[in]	eperiod	in microseconds

Definition at line 242 of file dshot_erps.c.

References DshotErps::ep, eperiodToPacked(), and packetToFrame().

Referenced by DshotErpsSetFromRpm().

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Variable Documentation

◆ gcrNibble

const uint8_t gcrNibble[16]

static

Initial value:

= {
  0x19, 0x1B, 0x12, 0x13, 0x1D, 0x15, 0x16, 0x17,
  0x1A, 0x09, 0x0A, 0x0B, 0x1E, 0x0D, 0x0E, 0x0F}

IBM GCR encoding lookup table.

Definition at line 8 of file dshot_erps.c.

Referenced by gcrEncode().

◆ gcrNibbleInv

const uint8_t gcrNibbleInv[32]

static

Initial value:

= {
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
  0xff, 0x9, 0xa, 0xb, 0xff, 0xd, 0xe, 0xf, 
  0xff, 0xff, 0x2, 0x3, 0xff, 0x5, 0x6, 0x7, 
  0xff, 0x0, 0x8, 0x1, 0xff, 0x4, 0xc, 0xff}

IBM GCR decoding lookup table.

Definition at line 15 of file dshot_erps.c.

Referenced by gcrDecode().

Functions

Variables

Function Documentation

◆ crc4()

◆ DshotErpsCheckCrc4()

◆ DshotErpsGetEperiod()

◆ DshotErpsGetRpm()

◆ DshotErpsSetFromFrame()

◆ DshotErpsSetFromRpm()

◆ eperiodDecode()

◆ eperiodEncode()

◆ eperiodToPacked()

◆ frameToPacket()

◆ gcrDecode()

◆ gcrEncode()

◆ greyDecode()

◆ greyEncode()

◆ packetToFrame()

◆ setFromEperiod()

Variable Documentation

◆ gcrNibble

◆ gcrNibbleInv