* Apply SX1262 register 0x8B5 patch for improved GC1109 RX sensitivity
Sets the LSB of undocumented SX1262 register 0x8B5 on Heltec V4 and
Wireless Tracker V2 boards with the GC1109 FEM. This patch was
recommended by Heltec/Semtech and tested in MeshCore PR #1398, where
it significantly reduced packet loss on the Heltec V4.
* Use higher level function
* Add .venv/ to .gitignore
* Hold GC1109 PA_POWER and PA_EN during deep sleep for LNA RX wake
Use rtc_gpio_hold_en to latch PA_POWER (LDO) and PA_EN (CSD) HIGH
during deep sleep so the GC1109 LNA remains powered for wake-on-packet
RX. Previously these pins used weak pull-ups which could lose state.
On deep sleep wake, skip these pins in the blanket RTC hold release and
instead release them in SX126xInterface::init() after GPIO registers are
set HIGH first, avoiding a power glitch on the GC1109.
Trade-off: ~6.5mA additional deep sleep current for significantly
improved wake-on-packet RX sensitivity (~17dB).
Reference: https://github.com/meshcore-dev/MeshCore/pull/1600
* Add LDO startup delay before GC1109 chip enable
TLV75733P LDO has ~550us startup time (datasheet tSTR). On cold boot,
wait 1ms for VBAT to stabilise before driving CSD/CPS, per GC1109
power-on sequence requirement. On deep sleep wake the LDO is held on
via RTC latch so no delay is needed.
The previous PSK check was broken from its introduction in #4643 —
memcmp was used in boolean context without comparing to 0, inverting
the condition. Since no one noticed for over a year, the PSK-based
filtering provided no practical value. Simplifying to always respect
the sender's preference is both more correct and easier to reason about.
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