change DEBUG optimization option from O0 to Og

add uart write to board test example

hw/bsp/board.h

@@ -107,10 +107,10 @@ static inline void board_delay(uint32_t ms)
   }
 }
 
-static inline int8_t board_uart_getchar(void)
+static inline int board_uart_getchar(void)
 {
   uint8_t c;
-  return board_uart_read(&c, 1) ? c : (-1);
+  return board_uart_read(&c, 1) ? (int) c : (-1);
 }
 
 static inline int board_uart_putchar(uint8_t c)

hw/bsp/pca10056/pca10056.c

@@ -156,6 +156,7 @@ int board_uart_read(uint8_t* buf, int len)
   (void) buf;
   (void) len;
   return 0;
+//  return NRFX_SUCCESS == nrfx_uart_rx(&_uart_id, buf, (size_t) len) ? len : 0;
 }
 
 int board_uart_write(void const * buf, int len)