From 4d821b2c9139e735155716b721ba0132fb7aca02 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Mon, 23 Oct 2023 18:42:21 +1100
Subject: [PATCH] AP_BattMonitor: added get_cell_voltage() for scripting

---
 libraries/AP_BattMonitor/AP_BattMonitor.cpp | 17 +++++++++++++++++
 libraries/AP_BattMonitor/AP_BattMonitor.h   |  3 +++
 2 files changed, 20 insertions(+)

diff --git a/libraries/AP_BattMonitor/AP_BattMonitor.cpp b/libraries/AP_BattMonitor/AP_BattMonitor.cpp
index ca73aab478e86e..5f1ecf8f7382d5 100644
--- a/libraries/AP_BattMonitor/AP_BattMonitor.cpp
+++ b/libraries/AP_BattMonitor/AP_BattMonitor.cpp
@@ -874,6 +874,23 @@ const AP_BattMonitor::cells & AP_BattMonitor::get_cell_voltages(const uint8_t in
     }
 }
 
+// get once cell voltage (for scripting)
+bool AP_BattMonitor::get_cell_voltage(uint8_t instance, uint8_t cell, float &voltage) const
+{
+    if (!has_cell_voltages(instance) ||
+        cell >= AP_BATT_MONITOR_CELLS_MAX) {
+        return false;
+    }
+    const auto &cell_voltages = get_cell_voltages(instance);
+    const uint16_t voltage_mv = cell_voltages.cells[cell];
+    if (voltage_mv == 0 || voltage_mv == UINT16_MAX) {
+        // UINT16_MAX is used as invalid indicator
+        return false;
+    }
+    voltage = voltage_mv*0.001;
+    return true;
+}
+
 // returns true if there is a temperature reading
 bool AP_BattMonitor::get_temperature(float &temperature, const uint8_t instance) const
 {
diff --git a/libraries/AP_BattMonitor/AP_BattMonitor.h b/libraries/AP_BattMonitor/AP_BattMonitor.h
index bcd802bcce0710..78311d25412396 100644
--- a/libraries/AP_BattMonitor/AP_BattMonitor.h
+++ b/libraries/AP_BattMonitor/AP_BattMonitor.h
@@ -232,6 +232,9 @@ class AP_BattMonitor
     const cells &get_cell_voltages() const { return get_cell_voltages(AP_BATT_PRIMARY_INSTANCE); }
     const cells &get_cell_voltages(const uint8_t instance) const;
 
+    // get once cell voltage (for scripting)
+    bool get_cell_voltage(uint8_t instance, uint8_t cell, float &voltage) const;
+
     // temperature
     bool get_temperature(float &temperature) const { return get_temperature(temperature, AP_BATT_PRIMARY_INSTANCE); }
     bool get_temperature(float &temperature, const uint8_t instance) const;