Peter Barker 2f87db990f hwdef: keep PA15 pulled up in the YJUAV_A6SE_H743 bootloader
PA15 drives PWM1 on this board and is also JTDI, which the STM32H743
brings out of every reset, and out of power-on, with its internal
pull-up enabled. The M1 servo line is therefore held high from then
until the bootloader's board init reconfigured the pin as a floating
input. On logic-analyser captures of the real board that is 692us on a
warm reset, and 496us and 520us on two cold power-ons, one over USB and
one at 12V. Each of those is a pulse inside the range most servos
accept, and it sent the servo to an extreme.

Configure PA15 as an input with pull-up in the bootloader instead, so
the line stays high continuously until the application switches the pin
to its timer, whose idle level is low. The servo then sees one high
lasting the whole bootloader, far outside any valid pulse width, rather
than a plausible command. Verified under Renode with the bootloader
held: PA15 reads input with pull-up while the bootloader owns the pins.
2026-09-17 22:56:37 +10:00
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ArduPilot is the most advanced, full-featured, and reliable open source autopilot software available. It has been under development since 2010 by a diverse team of professional engineers, computer scientists, and community contributors. Our autopilot software is capable of controlling almost any vehicle system imaginable, from conventional airplanes, quad planes, multi-rotors, and helicopters to rovers, boats, balance bots, and even submarines. It is continually being expanded to provide support for new emerging vehicle types.

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