The BMP180 driver had no public init method and never called
readCalibrationCoefficients() from anywhere -- _calCoeff ran at the
C++ in-class member-initializer defaults (all zeros) at runtime.
Consequence chain:
- computeB5(UT) short-circuited via 0/0 (Cortex-M7 SDIV with
SCB->CCR.DIV_0_TRP=0 returns 0 silently -- system_stm32f7xx.c does
not enable the trap)
- getPressure() always tripped the `if (B4 == 0)` guard, returning
the I2C-error sentinel (post-AUDIT-C17: INT32_MIN; pre-: 255)
- health watchdog at main.cpp:758 fired ERROR_BMP180_COMM every
main-loop iteration because last_bmp_check was only updated on the
success path, so the 15 s rate-limit never engaged once the check
started failing
- error_count > 10 latched system_emergency_state = true (per the
MCU-N1 fix), driving SAFE-MODE within ~25 s of every boot
Fix:
- Added BMP180::begin() public method: probes chip ID, then reads the
11 factory cal coefficients (registers 0xAA..0xBE step 2). Returns
true only on full success; false on chip-ID mismatch or any I2C
failure mid-loop.
- main.cpp BAROMETER INIT calls myBMP.begin() with up to 3 retries
(50 ms backoff) and sets a file-scope bmp180_operational flag.
Altitude-baseline loop now gated on success -- failure path leaves
RADAR_Altitude at 0.0f instead of letting pow(negative, fractional)
propagate NaN into gps_data telemetry.
- Health watchdog gates BMP180 check on bmp180_operational AND
updates last_bmp_check regardless of the error path. A single bad
pressure reading no longer tight-loops into SAFE-MODE; legit sensor
failure now takes the intended ~150 s (10 errors x 15 s) before
the MCU-N1 latch trips, giving the operator time to intervene.
Verification:
- new test_audit_cal_bmp180_begin.c, 3/3 PASS:
T1 every coefficient loaded in order with correct signed/unsigned types
T2 chip-mismatch and I2C-fail short-circuit semantics correct
T3 regression demo: zero-cal computeB5 returns 0 for any UT (the
silent-fail mode); datasheet cal reproduces 15.0 C
- full MCU regression 33/33 PASS (was 32/32; +1 new test, 0 regressions)
Bug introduced in 5fbe97f (initial upload of the driver from the
Arduino enjoyneering79 BMP180 library -- the begin()/init pattern from
the upstream Arduino version was lost in the STM32 port). Latent until
this audit cycle.
BMP180_ERROR=255 was an in-band sentinel returned by uint16_t I/O helpers
(read16, readRawTemperature) on I2C failure. 255 is also a valid uint16
register reading (0x00FF appears across the calibration block and is
reachable as a raw temperature/pressure sample), so a sensor failure was
indistinguishable from a real reading.
getTemperature() additionally narrowed the uint16_t raw read to int16_t
before passing to computeB5(). Raw bit-patterns >= 0x8000 (reachable across
the BMP180 -40..+85 C operating window) flipped to negative int16_t and
sign-extended into computeB5(), producing temperature errors of order
100s of C (e.g. -347 C instead of +51 C for raw UT = 0x8000).
Fix:
- Internal I/O helpers (read8/read16/readRawTemperature/readRawPressure)
now return bool and pass the value through an out-param. None of the
new sentinels collide with valid sensor output:
* getTemperature -> NaN on error
* getPressure -> INT32_MIN on error
* getSeaLevelPressure -> INT32_MIN on error
- getTemperature() keeps raw as uint16_t and widens value-preservingly
via (int32_t)raw before computeB5().
- readRawPressure() reads XLSB through the bool-out-param contract;
previously OR'd in 0xFF on I2C fail, silently corrupting the LSB.
Verification: test_audit_c17_bmp180_sentinel_and_cast 4/4 PASS, including
datasheet UT=27898 -> 15.0 C reproduction and 64/64 finite outputs across
a full uint16 sweep (vs 32/32 collapses in the upper half under the buggy
narrowing). Full MCU regression 32/32 PASS.
Caller-side: no external code references BMP180_ERROR; main.cpp's existing
range check at the health-watchdog catches INT32_MIN via the < 30000.0
branch.
- Add ERROR_COUNT sentinel to SystemError_t enum
- Change error_strings[] to static const char* const
- Add static_assert to enforce enum/array sync at compile time
- Add runtime bounds check with fallback for invalid error codes
- Add all missing test binary names to .gitignore
B12: PA IDQ calibration loop condition inverted (< 0.2 -> > 0.2) for both DAC1/DAC2
B13: DAC2 ADC buffer mismatch — reads from hadc2 now correctly stored to adc2_readings
B14: DIAG_SECTION macro call sites changed from 2-arg to 1-arg form (4 sites)
B15: htim3 definition + MX_TIM3_Init() added (PWM mode, CH2+CH3, Period=999)
B16: Removed stale NO-OP annotation on TriggerTimedSync (already fixed in Bug #3)
B17: Updated stale GPIO-only warnings to reflect TIM3 PWM implementation (Bug #5)
All 15 tests pass (11 original + 4 new for B12-B15).
Bug #9: Both TX and RX SPI init params had platform_ops = NULL, causing
adf4382_init() -> no_os_spi_init() to fail with -EINVAL. Fixed by setting
platform_ops = &stm32_spi_ops and passing stm32_spi_extra with correct CS
port/pin for each device.
Bug #10: stm32_spi_write_and_read() never toggled chip select. Since TX
and RX ADF4382A share SPI4, every register write hit both PLLs. Rewrote
stm32_spi.c to assert CS LOW before transfer and deassert HIGH after,
using stm32_spi_extra metadata. Backward-compatible: legacy callers
(e.g., AD9523) with cs_port=NULL skip CS management.
Also widened chip_select from uint8_t to uint16_t in no_os_spi.h since
STM32 GPIO_PIN_xx values (e.g., GPIO_PIN_14=0x4000) overflow uint8_t.
10/10 tests pass (8 original + 2 new regression tests).
