Merge branch 'earlephilhower:master' into master

Author: ladyada

README.md

@@ -25,6 +25,7 @@ Read the [Contributing Guide](https://github.com/earlephilhower/arduino-pico/blo
 * Adafruit KB2040
 * Adafruit Macropad RP2040
 * Adafruit Metro RP2040
+* Adafruit Metro RP2350
 * Adafruit QTPy RP2040
 * Adafruit STEMMA Friend RP2040
 * Adafruit Trinkey RP2040 QT

libraries/Wire/src/Wire.cpp

@@ -489,13 +489,25 @@ void TwoWire::flush(void) {
     // data transfer.
 }
 
+bool TwoWire::busIdle() {
+    // Check hardware status
+    uint32_t status = _i2c->hw->status;
+    bool tfe = (status & I2C_IC_STATUS_TFE_BITS);
+    bool mast = (status & I2C_IC_STATUS_MST_ACTIVITY_BITS);
+    return (tfe && !mast);
+}
+
 // DMA/asynchronous transfers.  Do not combime with synchronous runs or bad stuff will happen
 // All buffers must be valid for entire DMA and not touched until `finishedAsync()` returns true.
 bool TwoWire::writeReadAsync(uint8_t address, const void *wbuffer, size_t wbytes, const void *rbuffer, size_t rbytes, bool sendStop) {
     if (!_running || _txBegun || (wbytes == 0 && rbytes == 0)) {
         return false;
     }
 
+    if (!busIdle()) {
+        return false;
+    }
+
     if (!_dmaRunning) {
         beginAsync();
         if (!_dmaRunning) {

libraries/Wire/src/Wire.h

@@ -87,6 +87,7 @@ class TwoWire : public HardwareI2C {
     bool writeReadAsync(uint8_t address, const void *wbuffer, size_t wbytes, const void *rbuffer, size_t rbytes, bool sendStop = true);
     bool writeAsync(uint8_t address, const void *buffer, size_t bytes, bool sendStop = true);
     bool readAsync(uint8_t address, void *buffer, size_t bytes, bool sendStop = true);
+    bool busIdle();
     bool finishedAsync(); // Call to check if the async operations is completed and the buffer can be reused/read
     void abortAsync(); // Cancel an outstanding async I2C operation
     void onFinishedAsync(void(*function)(void)); // Set callback for async operation