charge_control: delay overload trigger by a configurable time

src/charge_control.c

@@ -27,7 +27,8 @@ static const char *DISCHARGE_STATE_TEXT[DISCHARGE_NUM_STATES] = {
 	"WAIT_CHARGEPUMP",
 	"OK",
 	"VOLTAGE_LOW",
-	"OVERCURRENT"
+	"OVERCURRENT",
+	"OVERCURRENT_DELAY"
 };
 
 static enum ChargeState charge_state;
@@ -55,6 +56,7 @@ static fxp_t u_bat_load_on;
 static fxp_t u_bat_load_off;
 
 static fxp_t load_current_limit;
+static fxp_t load_current_limit_delay;
 
 static fxp_t internal_temperature_limit;
 static fxp_t internal_temperature_recovery;
@@ -294,7 +296,13 @@ static void load_fsm_update(uint64_t uptime_ms, struct MeasurementResult *meas)
 
 			if((meas->i_load > load_current_limit)
 					&& (discharge_time_in_state > FLASH_CONFIG_LOAD_CURRENT_INRUSH_TIME)) {
+				if(load_current_limit_delay == 0) {
+					// switch off immediately
+					power_switch_load_off();
 					discharge_state = DISCHARGE_OVERCURRENT;
+				} else {
+					discharge_state = DISCHARGE_OVERCURRENT_DELAY;
+				}
 			}
 
 			if(meas->avg_u_bat < u_bat_load_off) {
@@ -311,17 +319,31 @@ static void load_fsm_update(uint64_t uptime_ms, struct MeasurementResult *meas)
 			// Can only switch on again after a specific amount of time has passed
 			if((meas->avg_u_bat > u_bat_load_on)
 					&& (discharge_time_in_state > FLASH_CONFIG_LOAD_ON_DELAY)) {
+				discharge_state = DISCHARGE_WAIT_CHARGEPUMP;
+			}
+			break;
+
+		case DISCHARGE_OVERCURRENT_DELAY:
+			if(meas->i_load < load_current_limit) {
+				// current recovered
 				discharge_state = DISCHARGE_OK;
+			} else if(discharge_time_in_state >= FLASH_CONFIG_OVERLOAD_DELAY_TIME) {
+				// switch off immediately
+				power_switch_load_off();
+				discharge_state = DISCHARGE_OVERCURRENT;
 			}
 			break;
 
 		case DISCHARGE_OVERCURRENT:
-			// Battery voltage is too low, so keep the load switched off
+			// Current limit reached
 			if(discharge_state_entered) {
 				power_switch_load_off();
 			}
 
-			// no way out except reset
+			// Overload recovery
+			if(discharge_time_in_state >= FLASH_CONFIG_OVERLOAD_RETRY_TIME) {
+				discharge_state = DISCHARGE_WAIT_CHARGEPUMP;
+			}
 			break;
 
 		default:

src/charge_control.h

@@ -27,6 +27,7 @@ enum DischargeState
 	DISCHARGE_OK,
 	DISCHARGE_VOLTAGE_LOW,
 	DISCHARGE_OVERCURRENT,
+	DISCHARGE_OVERCURRENT_DELAY,
 
 	DISCHARGE_NUM_STATES
 };

src/flash_config.h

@@ -86,6 +86,10 @@ extern uint8_t __conf_start;
  * time after load power-on. */
 #define FLASH_CONFIG_LOAD_CURRENT_INRUSH_TIME (*(uint32_t*)(FLASH_CONFIG_BASE_PTR + 0x0144))
 
+/* Inrush tolerance time (in ms). Overload protection is not enforced for this
+ * time after load power-on. */
+#define FLASH_CONFIG_LOAD_CURRENT_INRUSH_TIME (*(uint32_t*)(FLASH_CONFIG_BASE_PTR + 0x0144))
+
 /* Minimum voltage that the charge pump must produce above U_bat before any
  * power FET is switched on (in mV). */
 #define FLASH_CONFIG_MIN_CHARGE_PUMP_EXCESS_VOLTAGE (*(int32_t*)(FLASH_CONFIG_BASE_PTR + 0x0148))
@@ -93,6 +97,14 @@ extern uint8_t __conf_start;
 /* The minimum time the load must be off before it can be switched on again (in ms). */
 #define FLASH_CONFIG_LOAD_ON_DELAY (*(uint32_t*)(FLASH_CONFIG_BASE_PTR + 0x014c))
 
+/* Overload delay time (in ms). If load current is too high for this duration,
+ * load is switched permanently off. */
+#define FLASH_CONFIG_OVERLOAD_DELAY_TIME (*(uint32_t*)(FLASH_CONFIG_BASE_PTR + 0x0170))
+
+/* Overload retry time (in ms). Load is switched on again after this time if
+ * overload condition has triggered. */
+#define FLASH_CONFIG_OVERLOAD_RETRY_TIME (*(uint32_t*)(FLASH_CONFIG_BASE_PTR + 0x0174))
+
 
 /* Measurement Averaging:
  * Alpha is specified in units of 1/1000. 1000 means that only the latest
@@ -123,6 +135,8 @@ extern uint8_t __conf_start;
 /* Deep sleep duration (in seconds). */
 #define FLASH_CONFIG_DEEPSLEEP_DURATION (*(uint32_t*)(FLASH_CONFIG_BASE_PTR + 0x016c))
 
+/* FIXME: next free memory location: 0x178. Update when adding a value! */
+
 
 /* Functions */
 

utils/config_b26.yaml

@@ -79,6 +79,14 @@ config:
   # time after load power-on.
   LOAD_CURRENT_INRUSH_TIME: 10
 
+  # Overload delay time (in ms). If load current is too high for this duration,
+  # load is switched permanently off.
+  FLASH_CONFIG_OVERLOAD_DELAY_TIME: 10
+
+  # Overload retry time (in ms). Load is switched on again after this time if
+  # overload condition has triggered.
+  FLASH_CONFIG_OVERLOAD_RETRY_TIME: 1800000
+
   # Minimum voltage that the charge pump must produce above U_bat before any
   # power FET is switched on (in mV).
   MIN_CHARGE_PUMP_EXCESS_VOLTAGE: 10000

utils/config_to_hex.py

@@ -45,6 +45,8 @@ CONFIG_KEY_TO_OFFSET = {
         "AVG_ALPHA_TEMP":                   0x0164,
         "DEEPSLEEP_DELAY":                  0x0168,
         "DEEPSLEEP_DURATION":               0x016c,
+        "FLASH_CONFIG_OVERLOAD_DELAY_TIME": 0x0170,
+        "FLASH_CONFIG_OVERLOAD_RETRY_TIME": 0x0174
     }