Heatmap incorrect matrix effect workaround (#16315)

1 files changed, 7 insertions, 6 deletions

diff --git a/docs/feature_rgb_matrix.md b/docs/feature_rgb_matrix.md
index a8793be328..b2fc61e51e 100644
--- a/docs/feature_rgb_matrix.md
+++ b/docs/feature_rgb_matrix.md
@@ -657,18 +657,19 @@ You can enable a single effect by defining `ENABLE_[EFFECT_NAME]` in your `confi
 
 ### RGB Matrix Effect Typing Heatmap :id=rgb-matrix-effect-typing-heatmap
 
-This effect will color the RGB matrix according to a heatmap of recently pressed
-keys. Whenever a key is pressed its "temperature" increases as well as that of
-its neighboring keys. The temperature of each key is then decreased
-automatically every 25 milliseconds by default.
+This effect will color the RGB matrix according to a heatmap of recently pressed keys. Whenever a key is pressed its "temperature" increases as well as that of its neighboring keys. The temperature of each key is then decreased automatically every 25 milliseconds by default.
 
-In order to change the delay of temperature decrease define
-`RGB_MATRIX_TYPING_HEATMAP_DECREASE_DELAY_MS`:
+In order to change the delay of temperature decrease define `RGB_MATRIX_TYPING_HEATMAP_DECREASE_DELAY_MS`:
 
 ```c
 #define RGB_MATRIX_TYPING_HEATMAP_DECREASE_DELAY_MS 50
 ```
 
+Heatmap effect may not light up the correct adjacent LEDs for certain key matrix layout such as split keyboards. The following define will limit the effect to pressed keys only:
+```c
+#define RGB_MATRIX_TYPING_HEATMAP_SLIM
+```
+
 ## Custom RGB Matrix Effects :id=custom-rgb-matrix-effects
 
 By setting `RGB_MATRIX_CUSTOM_USER = yes` in `rules.mk`, new effects can be defined directly from your keymap or userspace, without having to edit any QMK core files. To declare new effects, create a `rgb_matrix_user.inc` file in the user keymap directory or userspace folder.