MITO 8M Nano SOM/MITO 8M Nano Evaluation Kit/Interfaces and Connectors/UARTs

History
Version	Issue Date	Notes
1.0.0	May 2022	First release

UARTs interface

Description

The UARTs interface available on the Evaluation Kit are mapped to the following connectors:

• J21 is a standard DB9 male connector for the configurable UART1 port. The board provides some configuration options for the selection of the UART mode (RS232/RS422/RS485 with auto-direction)

DB9 configuration

• J25 is a 6x1x2.54mm horizontal socket header for the UART3 port. This is a Digilent Pmod™ Compatible connector for the UART Pmod™ Compatiblemodule (6-Pin Pmod™ Compatible Connector Digilent Pmod™ Interface Specification Type 4 UART)

PMOD configuration

Signals

The following tables describes the interface signals

UART1

In the schematics page 13, the signals label are referring to the original AXEL Lite EVK SOM's signals. UART5 is referencing the AXEL Lite UART connection and should be used just as a signal labels. For MITO 8M mini/Nano EVK, the UART connected is UART1

Pin#	SOM Pin#	Pin name	RS-232	RS-422	RS-485
1	-	Not connected	Not connected	Not connected	Not connected
2	J10.95	UART5_A	UART5 receive line	UART5_A	UART5_A
3	J10.93	UART5_Y	UART5 transmit line	UART5_Y	UART5_A
4	-	Not connected	Not connected	Not connected	Not connected
5	-	DGND	Ground	Ground	Ground
6	-	Not connected	Not connected	Not connected	Not connected
7	J10.105	UART5_Z	UART5 Request To Send	UART5_Z	UART5_B
8	J10.107	UART5_B	UART5 Clear To Send	UART5_B	UART5_B
9	-	Not connected	Not connected	Not connected	Not connected

The J19 and J20 jumpers are used to configure the UART mode, as reported below:

Jumper	RS232 mode	RS422 mode	RS485 mode
1-3	open	open	closed
5-7	open	closed	open
9-11	open	closed	open
2-4	open	open	closed
6-8	open	closed	closed
10-12	open	closed	closed
13-15	open	open	closed
14-16	open	open	closed

J19 and J20 connectors

UART5 jumper configuration

UART3

Pin#	SOM Pin#	Pin name	Pin function	Pin Notes
1	J10.50	PMOD_A0	Clear to send
2	J10.89	PMOD_A1	Transmit data
3	J10.91	PMOD_A2	Receive data
4	J10.40	PMOD_A3	Request to send
5	-	DGND	Ground
6	-	3V3	+3.3 V

Device mapping

• UART1 is mapped to /dev/ttymxc1 device in Linux
• UART3 is mapped to /dev/ttymxc2 device in Linux

Device usage

• UART1 is a MultiProtocol that supports (after hardware Jumper configuration) the RS232, RS4222 or RS485 protocols. The related device tree file has to be properly configured too for enabling the GPIO transceiver configuration.
• UART3 can be used with a PMOD adapter or with a TTL peripheral

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