groundwork for BMS

src/max17048.c

@@ -0,0 +1,44 @@
+#include "max17048.h"
+#include "esp_err.h"
+#include "i2c.h"
+#include "esp_timer.h"
+
+static const char *TAG = "BATTERY";
+uint8_t established_soc;
+
+esp_err_t max17048_init() {
+  esp_err_t err = ESP_OK;
+  uint8_t status, _;
+  err |= i2c_init();
+  err |= max17048_read_reg(MAX17048_REG_STATUS, &status, &_);
+  err |= bms_set_alert_bound_voltages(3.3, 4.2);
+  err |= bms_set_reset_voltage(3.25);
+  err |= bms_set_alsc();
+  err |= bms_clear_status();
+
+}
+
+// Helper: Function reading MAX17048 SOC register, returning battery percentage
+uint8_t bms_get_soc() {
+  // uint16_t raw_soc, raw_vcell;
+  uint16_t raw_soc;
+
+  // Read SOC (Register 0x04)
+  if (max17048_read_reg(MAX17048_REG_SOC, ((uint8_t*)&raw_soc)+1, (uint8_t*)&raw_soc) == ESP_OK) {
+    return (raw_soc >> 8) + raw_soc & 0x80; // round to the nearest percent
+  } else {
+    ESP_LOGE(TAG, "Failed to read MAX17048");
+    return 0;
+  }
+}
+
+esp_err_t bms_set_alert_bound_voltages(float min, float max) {
+  uint8_t minVal = (uint16_t)((float)min * 1000.0) / 20;
+  uint8_t maxVal = (uint16_t)((float)max * 1000.0) / 20;
+  return max17048_write_reg(MAX17048_REG_VALRT, minVal, maxVal);
+}
+
+esp_err_t bms_set_reset_voltage(float vreset) {
+  uint8_t maxVal = (uint16_t)((float)vreset * 1000.0) / 40;
+  max17048_write_reg(MAX17048_REG_VRST_ID, vreset, 0);
+}