fix mode 3

Adafruit_SPIDevice.cpp

@@ -213,11 +213,34 @@ void Adafruit_SPIDevice::transfer(uint8_t *buffer, size_t len) {
           if (BUSIO_READ_MISO())
             reply |= b;
         }
+        
+        BUSIO_SET_CLOCK_LOW();
+        
+      } else if (_dataMode == SPI_MODE3) {
+        
+        if (_mosi != -1) {   // transmit on falling edge
+          BUSIO_WRITE_MOSI(send & b);
         }
         
         BUSIO_SET_CLOCK_LOW();
         
-      } else { // if (_dataMode == SPI_MODE1 || _dataMode == SPI_MODE3)
+        if (bitdelay_us) {
+          delayMicroseconds(bitdelay_us);
+        }
+        
+        BUSIO_SET_CLOCK_HIGH();
+        
+        if (bitdelay_us) {
+          delayMicroseconds(bitdelay_us);
+        }
+        
+        if (_miso != -1) {  // read on rising edge
+          if (BUSIO_READ_MISO()) {
+            reply |= b;
+          }
+        }
+      
+      }  else { // || _dataMode == SPI_MODE1)
         
         BUSIO_SET_CLOCK_HIGH();
         
@@ -237,11 +260,11 @@ void Adafruit_SPIDevice::transfer(uint8_t *buffer, size_t len) {
           }
         }
       }
+    }
     if (_miso != -1) {
       buffer[i] = reply;
     }
   }
-  }
   return;
 }