# Aria G25 - Enable DMA on the serial ports to avoid rx overruns

##Problem

Sometimes the serial port losts some incoming characters. 

##Solution

To solve this problem enable inside the Device Tree file DMA for the serial port you are using.

###/dev/ttyS1

	usart0: serial@f801c000 {
		pinctrl-0 = <&pinctrl_usart0 &pinctrl_usart0_rts &pinctrl_usart0_cts>;
		status = "okay";
		atmel,use-dma-rx;
		atmel,use-dma-tx;
		dmas = <&dma0 2 0x3>,
		   <&dma0 2 0x204>;
		dma-names = "tx", "rx";
	};


###/dev/ttyS2

	usart1: serial@f8020000 {
		pinctrl-0 = <&pinctrl_usart1 &pinctrl_usart1_rts &pinctrl_usart1_cts>;
		status = "okay";
		atmel,use-dma-rx;
		atmel,use-dma-tx;
		dmas = <&dma0 2 0x5>,
		   <&dma0 2 0x206>;
		dma-names = "tx", "rx";
	};

<!--

###/dev/ttyS3

<pre class="terminal">
      usart2: serial@f8024000 {
        pinctrl-0 = <&pinctrl_usart2>;
        status = "okay";
        atmel,use-dma-rx;
        atmel,use-dma-tx;
        dmas = <&dma0 2 0x7>,
           <&dma0 2 0x208>;
        dma-names = "tx", "rx";
      };
</pre>
-->

To compile know how to compile the Device Tree follow the tutorial on the Kernel Compilation
listed in the [Tutorial Index](/tutorials).

@include='bio_tanzilli'