# How to use the SERIAL ports on Acqua

<abstract>
This article illustrates how to activate and use the serial ports available on Acqua A5
</abstract>

## Pinout and device tree definitions port by port

### USART0

| Signal  | Dir | Description        | Pin          |
|---------|-----|--------------------|--------------|
| TXD0    | O   | Transmit data      | J2.14 (PD18) |
| RXD0    | I   | Receive data       | J2.11 (PD17) |
| RTS0    | O   | Request to send    | J2.12 (PD16) |
| CTS0    | I   | Clear to send      | J2.9  (PD15) |


	usart0: serial@f001c000 {
		status = "okay";
	};
	
### USART1

| Signal  | Dir | Description        | Pin          |
|---------|-----|--------------------|--------------|
| TXD1    | O   | Transmit data      | J2.46 (PB29) |
| RXD1    | I   | Receive data       | J2.45 (PB28) |

	usart1: serial@f0020000 {
		status = "okay";
	};
	

### USART2

| Signal  | Dir | Description        | Pin          |
|---------|-----|--------------------|--------------|
| TXD2    | O   | Transmit data      | J3.13 (PE26) |
| RXD2    | I   | Receive data       | J3.12 (PE25) |
| RTS2    | O   | Request to send    | J3.11 (PE24) |
| CTS2    | I   | Clear to send      | J3.10 (PE23) |

	usart2: serial@f8020000 {
		status = "okay";
	};


### USART3


| Signal  | Dir | Description        | Pin          |
|---------|-----|--------------------|--------------|
| TXD3    | O   | Transmit data      | J3.7  (PE19) |
| RXD3    | I   | Receive data       | J3.8  (PE18) |
| RTS3    | O   | Request to send    | J3.5  (PE17) |
| CTS3    | I   | Clear to send      | J3.6  (PE16) |

	usart3: serial@f8024000 {
		status = "okay";
	};

### UART0


| Signal  | Dir | Description        | Pin          |
|---------|-----|--------------------|--------------|
| UTXD0   | O   | Transmit data      | J3.30 (PC30) |
| URXD0   | I   | Receive data       | J3.31 (PC29) |

	uart0: serial@f0024000 {
		status = "okay";
	};


### UART1


| Signal  | Dir | Description        | Pin          |
|---------|-----|--------------------|--------------|
| UTXD1   | O   | Transmit data      | J3.41 (PA31) |
| URXD1   | I   | Receive data       | J3.32 (PA30) |

	uart1: serial@f8028000 {
		status = "okay";
	};

### Debug port


| Signal  | Dir | Description        | Pin          |
|---------|-----|--------------------|--------------|
| DTXD    | O   | Debug port tx data | J3.4  (PB31) |
| DRXD    | I   | Debug port rx data | J3.3  (PB30) |


##Related links

* @article='acqua_compile_kernel_4_19' (This article includes the instructions to compile the device tree file)
* [Atmel usart binding](https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/Documentation/devicetree/bindings/serial/atmel-usart.txt?id=refs/tags/v3.13.11)
* [DMA bindings](https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/Documentation/devicetree/bindings/dma/atmel-dma.txt?id=refs/tags/v3.13.11)


@include='bio_tanzilli'