Betaflight: Possible Bidirectional DSHOT bug (unsure if it's Betaflight)

[kenthinson]

Describe the bug
Enabling Bidirectional DSHOT doesn't work.

To Reproduce
Enable Bidirectional DSHOT. Once I enable bidirectional then Plugging in the battery I get only the first half of the esc startup sound. If I check the motor tab of Betaflight configurator I see 100% error rate. On the Setup tab under info I see "Flags: DSHOT_BBANG"

Expected behavior
Bidirectional DSHOT works.

Flight controller configuration

# 

# diff all

# version
# Betaflight / STM32F411 (S411) 4.1.4 Feb  4 2020 / 17:26:13 (bc9715eec) MSP API: 1.42
# manufacturer_id: TTRH   board_name: TRANSTECF411HD   custom defaults: YES

# start the command batch
batch start

# reset configuration to default settings
defaults nosave

board_name TRANSTECF411HD
manufacturer_id TTRH
mcu_id 0051003d3339511539363632
signature 

# name: TransTEC

# master
set dshot_bidir = ON

profile 0

profile 1

profile 2

# restore original profile selection
profile 0

rateprofile 0

rateprofile 1

rateprofile 2

rateprofile 3

rateprofile 4

rateprofile 5

# restore original rateprofile selection
rateprofile 0

# save configuration
save
# 

Allocation list

# 

# resource show all
Currently active IO resource assignments:
(reboot to update)
--------------------
A00: ADC_BATT
A01: GYRO_EXTI
A02: SERIAL_TX 2
A03: SERIAL_RX 2
A04: GYRO_CS 1
A05: SPI_SCK 1
A06: SPI_MISO 1
A07: SPI_MOSI 1
A08: LED_STRIP
A09: FREE
A10: SERIAL_RX 1
A11: USB
A12: USB
A13: FREE
A14: LED 1
A15: FREE
B00: MOTOR 1
B01: MOTOR 2
B02: FREE
B03: FREE
B04: FREE
B05: FREE
B06: BEEPER
B07: FREE
B08: FREE
B09: MOTOR 4
B10: MOTOR 3
B11: FREE
B12: PREINIT 2
B13: FREE
B14: FREE
B15: FREE
C00: FREE
C01: FREE
C02: FREE
C03: FREE
C04: FREE
C05: FREE
C06: FREE
C07: FREE
C08: FREE
C09: FREE
C10: FREE
C11: FREE
C12: FREE
C13: INVERTER 1
C14: FREE
C15: FREE
D00: FREE
D01: FREE
D02: FREE
D03: FREE
D04: FREE
D05: FREE
D06: FREE
D07: FREE
D08: FREE
D09: FREE
D10: FREE
D11: FREE
D12: FREE
D13: FREE
D14: FREE
D15: FREE
E00: FREE
E01: FREE
E02: FREE
E03: FREE
E04: FREE
E05: FREE
E06: FREE
E07: FREE
E08: FREE
E09: FREE
E10: FREE
E11: FREE
E12: FREE
E13: FREE
E14: FREE
E15: FREE

Currently active Timers:
-----------------------
TIM1:
    CH1: LED_STRIP
TIM2: FREE
TIM3: FREE
TIM4: FREE
TIM5: FREE
TIM6: FREE
TIM7: FREE
TIM9: FREE
TIM10: FREE
TIM11: FREE

Currently active DMA:
--------------------
DMA1 Stream 0: FREE
DMA1 Stream 1: FREE
DMA1 Stream 2: FREE
DMA1 Stream 3: FREE
DMA1 Stream 4: FREE
DMA1 Stream 5: FREE
DMA1 Stream 6: FREE
DMA1 Stream 7: FREE
DMA2 Stream 0: ADC 1
DMA2 Stream 1: FREE
DMA2 Stream 2: FREE
DMA2 Stream 3: FREE
DMA2 Stream 4: FREE
DMA2 Stream 5: FREE
DMA2 Stream 6: LED_STRIP
DMA2 Stream 7: FREE

# 

Setup / Versions
TransTEC Beetle HOM HD CineWhoop RTF
TRANSTECF411HD
ESC: J-H-30

Additional context
Can anyone advise me how to start looking at logs to trace this down? I'm fully aware this may not be a Betaflight issue.

[kenthinson]

@mikeller I believe I added all the missing info from the template. Sorry.

[kenthinson]

After more googling I found the solution on the Facebook group.

dshot_bitbang = ON
feature -LED_STRIP

[vinz486]

Hi, i'm just fixed the same issue, using this board (no rx version): https://betafpv.com/products/f4-1s-aio-brushless-flight-controller?variant=34861563019398

ESC is Jazz, 96khz, with telemetry.

But, I had to set:
dshot_bitbang = OFF

Tried AUTO (default) and ON: not working.

Led strip is unrelated for me.

Thankfully I found your post @kenthinson, I was going crazy and I think many people will do too.

What's this bitbang? Never heard.