BQ25756

Hardware-agnostic driver for the TI BQ25756 — a 1S-28S NVDC synchronous switch-mode battery charger with bidirectional (OTG / reverse-boost) operation, an integrated 7-channel ADC (VBUS / IBUS / VBAT / IBAT / VSYS / TS / TDIE), JEITA temperature handling, watchdog, and safety/charge timers.

Layout

include/
  bq25756.h            public API (~280 LOC)
  bq25756_registers.h  register addresses, bit masks, LSB step sizes
  bq25756_types.h      enums, HAL struct, device handle, config struct
src/
  bq25756.c            implementation
CMakeLists.txt         tri-mode build (ESP-IDF / Zephyr / plain CMake)

Integrating

1. Provide a BQ25756HAL with three callbacks:
   • readReg(i2c_addr, reg, data, length)
   • writeReg(i2c_addr, reg, data, length)
   • delayMs(ms) All three must return 0 on success.
2. Call bq25756Init(&dev, &hal, BQ25756_I2C_ADDR_DEFAULT). The driver reads PART_INFO and verifies the PN nibble.
3. Build a BQ25756Config and pass it to bq25756ApplyConfig(), or call the individual setters one at a time.
4. Poll bq25756GetStatus() / bq25756GetFaults() and pet the watchdog with bq25756KickWatchdog() on whatever cadence you've programmed.

BENCH-VERIFY

The driver was authored without access to the live TI SLUSF42 datasheet (WebFetch was unavailable). Every register address, bit position, and LSB step is annotated BENCH-VERIFY in bq25756_registers.h. On first power-up: dump the 0x00..0x55 register map and diff against the printed datasheet before trusting any setter in production.

Reference

• TI BQ25756 datasheet (SLUSF42): https://www.ti.com/lit/ds/symlink/bq25756.pdf