battery_monitor_demo Directory Reference

Directory dependency graph for battery_monitor_demo:

Directories
	src

Detailed Description

Reads battery state-of-charge from a MAX17048-class I2C fuel gauge (7-bit address 0x36) through ra8_smbus on the IIC_B bus, on the Pmod1 I2C side (P511/SDA1 + P512/SCL1), and folds each reading into the ra8_batt nag policy.

The gauge is a plain register-indexed I2C device, so it answers the SMBus byte protocols natively. Two registers carry everything the app needs, each in a single byte read:

• SOC (0x04) – the high byte is the integer percent.
• CRATE (0x16) – the high byte's sign bit is 0 while charging and 1 while discharging, so one byte gives the charge direction.

A NAK – no fuel gauge fitted – halts on a BKPT before any PASS line, so the gate cannot pass by accident. g_bat_soc, g_bat_chg, g_bat_nag and g_bat_heartbeat mirror the result for headless probing.

Low-battery nag

libs/ra8_batt raises a one-shot warning on the descent into each band. It is edge-triggered with hysteresis: a band warns once, stays quiet while the battery sits in it, and re-arms only after SOC recovers past the threshold by k_ra8_batt_rearm_margin or while charging – so a steady or jittering low battery does not spam, and charging suppresses warnings outright. The decision logic is pure (no MMIO), so it is host-unit-tested with full MC/DC in tests/misc/src/test_ra8_batt.c; this app is the on-target consumer.

Blocked on

The EK-RA8D2 has no native fuel gauge, so a stock board only ever prints the NAK banner – the part has to be fitted before a bench run means anything. ra8_emulator does model the gauge on the modelled IIC_B bus, so the SOC and CRATE reads return through the genuine ra8_smbus -> ra8_i3c path with no stub, and the percent and charge state can be driven off-target.