From f203cf321ffc8a37254eefecb663161564bfbf68 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Mon, 23 Jan 2023 17:15:58 +1100
Subject: [PATCH] AP_Compass: fixed field orientation for MMC3416

the sensor is not FRD, and needs Y axis reversed to follow ArduPilot
FRD convention for magnetometers
---
 libraries/AP_Compass/AP_Compass_MMC3416.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libraries/AP_Compass/AP_Compass_MMC3416.cpp b/libraries/AP_Compass/AP_Compass_MMC3416.cpp
index d7ba223e16..5177a74be6 100644
--- a/libraries/AP_Compass/AP_Compass_MMC3416.cpp
+++ b/libraries/AP_Compass/AP_Compass_MMC3416.cpp
@@ -247,6 +247,10 @@ void AP_Compass_MMC3416::timer()
 #endif
 
         last_sample_ms = AP_HAL::millis();
+
+        // sensor is not FRD
+        field.y = -field.y;
+
         accumulate_sample(field, compass_instance);
 
         if (!dev->write_register(REG_CONTROL0, REG_CONTROL0_TM)) {
@@ -273,6 +277,9 @@ void AP_Compass_MMC3416::timer()
         field *= -counts_to_milliGauss;
         field += offset;
 
+        // sensor is not FRD
+        field.y = -field.y;
+
         last_sample_ms = AP_HAL::millis();
         accumulate_sample(field, compass_instance);