Merge pull request #139 from sparkfun/decrease_RX_ISR_Overhead

Increase performance of UART RX.

Author: Owen

cores/arduino/ard_sup/ap3_uart.h

@@ -30,11 +30,11 @@ SOFTWARE.
 #include "RingBuffer.h"
 
 #ifndef AP3_UART_RINGBUFF_SIZE
-#define AP3_UART_RINGBUFF_SIZE 256
+#define AP3_UART_RINGBUFF_SIZE 256 * 16
 #endif
 
 #ifndef AP3_UART_LINBUFF_SIZE
-#define AP3_UART_LINBUFF_SIZE 256
+#define AP3_UART_LINBUFF_SIZE 256 * 16
 #endif
 
 typedef RingBufferN<AP3_UART_RINGBUFF_SIZE> AP3UartRingBuffer;
@@ -78,7 +78,7 @@ class Uart : public HardwareSerial
 	operator bool() { return true; } // todo: wait for a serial terminal to be open... probably depends on RTS or CTS...
 
 private:
-public:													//temporary
+public:							  //temporary
 	AP3UartRingBuffer _rx_buffer; // These buffers guarantee the lifespan of the data to transmit
 	AP3UartRingBuffer _tx_buffer; //		to allow for asynchronous tranfsers
 

cores/arduino/ard_sup/uart/ap3_uart.cpp

@@ -543,19 +543,16 @@ inline void Uart::uart_isr(void)
             {
                 .ui32Direction = AM_HAL_UART_READ,
                 .pui8Data = (uint8_t *)&rx_c,
-                .ui32NumBytes = 1,
+                .ui32NumBytes = sizeof(rx_c),
                 .ui32TimeoutMs = 0,
                 .pui32BytesTransferred = &ui32BytesRead,
             };
 
-        do
+        am_hal_uart_transfer(_handle, &sRead);
+        if (ui32BytesRead)
         {
-            am_hal_uart_transfer(_handle, &sRead);
-            if (ui32BytesRead)
-            {
-                _rx_buffer.store_char(rx_c);
-            }
-        } while (ui32BytesRead);
+            _rx_buffer.store_char(rx_c);
+        }
     }
 }