Extend GPIO expander support to Buttons and Switches

Author: nseidle

Firmware/RTK_Everywhere/Buttons.ino

@@ -82,7 +82,7 @@ void IRAM_ATTR gpioExpanderISR()
 }
 
 // Start the I2C expander if possible
-bool beginGpioExpander(uint8_t padAddress)
+bool beginGpioExpanderButtons(uint8_t padAddress)
 {
     // Initialize the PCA95xx with its default I2C address
     if (io.begin(padAddress, *i2c_0) == true)
@@ -99,7 +99,7 @@ bool beginGpioExpander(uint8_t padAddress)
 
         systemPrintln("Directional pad online");
 
-        online.gpioExpander = true;
+        online.gpioExpanderButtons = true;
         return (true);
     }
     return (false);
@@ -114,7 +114,7 @@ void buttonRead()
         userBtn->read();
 
     // Check directional pad once interrupt has occurred
-    if (online.gpioExpander == true && gpioChanged == true)
+    if (online.gpioExpanderButtons == true && gpioChanged == true)
     {
         gpioChanged = false;
 
@@ -155,7 +155,7 @@ bool buttonReleased()
         return (userBtn->wasReleased());
 
     // Check directional pad
-    if (online.gpioExpander == true)
+    if (online.gpioExpanderButtons == true)
     {
         // Check for any button press on the directional pad
         for (int buttonNumber = 0; buttonNumber < 5; buttonNumber++)
@@ -179,7 +179,7 @@ bool buttonReleased(uint8_t buttonNumber)
         return (false);
 
     // Check directional pad
-    if (online.gpioExpander == true)
+    if (online.gpioExpanderButtons == true)
     {
         if (gpioExpander_wasReleased[buttonNumber] == true)
         {
@@ -206,7 +206,7 @@ bool buttonPressedFor(uint16_t maxTime)
 bool buttonPressedFor(uint8_t buttonNumber, uint16_t maxTime)
 {
     // Check directional pad
-    if (online.gpioExpander == true)
+    if (online.gpioExpanderButtons == true)
     {
         // Check if the time has started for this button
         if (gpioExpander_holdStart[buttonNumber] > 0)

Firmware/RTK_Everywhere/SD.ino

@@ -94,7 +94,7 @@ bool sdCardPresent(void)
             return (true); // Card detect high = SD in place
         return (false);    // Card detect low = No SD
     }
-    else if (present.microSdCardDetectGpioExpanderHigh == true && online.gpioExpander == true)
+    else if (present.microSdCardDetectGpioExpanderHigh == true && online.gpioExpanderButtons == true)
     {
         if (io.digitalRead(gpioExpander_cardDetect) == GPIO_EXPANDER_CARD_INSERTED)
             return (true); // Card detect high = SD in place

Firmware/RTK_Everywhere/System.ino

@@ -871,4 +871,76 @@ void getMacAddresses(uint8_t *macAddress, const char *name, esp_mac_type_t type,
     if (debug)
         systemPrintf("%02X:%02X:%02X:%02X:%02X:%02X - %s\r\n", macAddress[0], macAddress[1], macAddress[2],
                      macAddress[3], macAddress[4], macAddress[5], name);
-};
+}
+
+// Start the I2C GPIO expander responsible for switches (generally the RTK Flex)
+void beginGpioExpanderSwitches()
+{
+    if (present.gpioExpanderSwitches)
+    {
+        if (gpioExpanderSwitches == nullptr)
+            gpioExpanderSwitches = new SFE_PCA95XX(PCA95XX_PCA9534);
+
+        // In Flex, the GPIO Expander has been assigned address 0x21
+        if (gpioExpanderSwitches->begin(0x21, *i2c_0) == false)
+        {
+            systemPrintln("GPIO expander for switches not detected");
+            delete gpioExpanderSwitches;
+            gpioExpanderSwitches = nullptr;
+            return;
+        }
+
+        // SW1 is on pin 0. Driving it high will disconnect the ESP32 from USB
+        // GNSS_RST is on pin 5. Driving it low when an LG290P is connected will kill the I2C bus.
+        // PWRKILL is on pin 7. Driving it low will turn off the system
+        for (int i = 0; i < 8; i++)
+        {
+            //Set all pins to low expect GNSS RESET and PWRKILL
+            if (i == 5 || i == 7)
+                gpioExpanderSwitches->digitalWrite(i, HIGH);
+            else
+                gpioExpanderSwitches->digitalWrite(i, LOW);
+
+                gpioExpanderSwitches->pinMode(i, OUTPUT);
+        }
+
+        online.gpioExpanderSwitches = true;
+
+        systemPrintln("GPIO Expander for switches configuration complete");
+    }
+}
+
+// Drive GPIO pin high to bring GNSS out of reset
+void gpioExpanderGnssBoot()
+{
+    if (online.gpioExpanderSwitches == true)
+        gpioExpanderSwitches->digitalWrite(gpioExpanderSwitch_GNSS_Reset, HIGH);
+}
+
+void gpioExpanderGnssReset()
+{
+    if (online.gpioExpanderSwitches == true)
+    {
+        if (settings.detectedGnssReceiver != GNSS_RECEIVER_LG290P)
+        {
+            Serial.println("Driving GNSS reset LOW");
+            gpioExpanderSwitches->digitalWrite(gpioExpanderSwitch_GNSS_Reset, LOW);
+        }
+        else
+            systemPrintln("Skipped disable of LG290P"); // Disabling an LG290P when it's connected to an I2C bus will
+                                                        // bring down the I2C bus
+    }
+}
+
+// The IMU is on UART3 of the Flex module connected to switch 3
+void gpioExpanderSelectImu()
+{
+    if (online.gpioExpanderSwitches == true)
+        gpioExpanderSwitches->digitalWrite(gpioExpanderSwitch_S3, LOW);
+}
+
+void gpioExpanderSelectLora()
+{
+    if (online.gpioExpanderSwitches == true)
+        gpioExpanderSwitches->digitalWrite(gpioExpanderSwitch_S3, HIGH);
+}

Firmware/RTK_Everywhere/Tasks.ino

@@ -1825,7 +1825,7 @@ void buttonCheckTask(void *e)
 
                     forceDisplayUpdate = true; // User is interacting so repaint display quickly
 
-                    if (online.gpioExpander == true)
+                    if (online.gpioExpanderButtons == true)
                     {
                         // React to five different buttons
                         if (buttonLastPressed() == gpioExpander_up || buttonLastPressed() == gpioExpander_left)