2 files changed, 3 insertions, 4 deletions

diff --git a/keyboards/at_at/660m/chconf.h b/keyboards/at_at/660m/chconf.h
index 99fa8ce39..89388dd5a 100644
--- a/keyboards/at_at/660m/chconf.h
+++ b/keyboards/at_at/660m/chconf.h
@@ -105,10 +105,6 @@
  */
 #define CH_CFG_NO_IDLE_THREAD               FALSE
 
-/* Use __WFI in the idle thread for waiting. Does lower the power
- * consumption. */
-#define CORTEX_ENABLE_WFI_IDLE              TRUE
-
 /** @} */
 
 /*===========================================================================*/
diff --git a/keyboards/at_at/660m/rules.mk b/keyboards/at_at/660m/rules.mk
index b893d8031..0b3685f09 100644
--- a/keyboards/at_at/660m/rules.mk
+++ b/keyboards/at_at/660m/rules.mk
@@ -17,3 +17,6 @@ CUSTOM_MATRIX = no # Custom matrix file
 # RGBLIGHT_ENABLE = yes
 NO_USB_STARTUP_CHECK = yes # Workaround for issue 6369
 
+
+# Enter lower-power sleep mode when on the ChibiOS idle thread
+OPT_DEFS += -DCORTEX_ENABLE_WFI_IDLE=TRUE