Merge pull request #7 from korstiaanS/add-backlight-function

Forairaaaaa · web-flow · commit 595890d55c07 · 2025-09-10T14:44:59.000+08:00
Added LCD backlight function
diff --git a/src/M5StamPLC.cpp b/src/M5StamPLC.cpp
@@ -62,12 +62,20 @@ void M5_STAMPLC::io_expander_a_init()
     ioe.setDirection(5, true);
     ioe.setPullMode(5, false);
     ioe.setHighImpedance(5, true);
-
+  
     ioe.setDirection(6, true);
     ioe.setPullMode(6, false);
     ioe.setHighImpedance(6, true);
 }
 
+void M5_STAMPLC::setBacklight(bool on)
+{
+    auto& ioe = M5.getIOExpander(0);
+
+    ioe.setHighImpedance(7, !on);
+    ioe.digitalWrite(7, !on); // backlight is active low
+}
+
 void M5_STAMPLC::setStatusLight(const uint8_t& r, const uint8_t& g, const uint8_t& b)
 {
     auto& ioe = M5.getIOExpander(0);
diff --git a/src/M5StamPLC.h b/src/M5StamPLC.h
@@ -58,6 +58,13 @@ class M5_STAMPLC {
      */
     void setStatusLight(const uint8_t& r, const uint8_t& g, const uint8_t& b);
 
+    /**
+     * @brief Control the LCD backlight
+     *
+     * @param on true to turn backlight ON, false to turn it OFF
+     */
+    void setBacklight(bool on);
+
     /**
      * @brief Read PLC Input
      *
