RS232 - Serial Port

The RS232 class provides a wrapper for basic UART functionality for RS232#1.
It offers basic functions to configure, send and receive data.

The class needs to be initialized with the following parameters:

Parameter name	Value	Description
uart_baudrate	9600, 19200, 38400, 57600, 115200, 230400, 460800, 921600	RS232#1 baudrate

Methods

class RS232(uart_baudrate, uart_rxbuf=4096)

The RS232 class is used to create an object that can communicate via the RS232 connector available on the SBC.

Important

The class described in this section applies only to RS232#1, which is entirely programable. RS232#2 is non-programmable and is hard-wired see system schematic.
GPS2 and GPS3 should be powered on in order to use RS232#2.
Example to turn ON GPS2 and GPS3 in order to use RS232#2:

>>> import sbc
>>> pm = sbc.Power_Module()
>>> pm.gps2and3_on()

The class needs to be initialized with the following parameters:

Parameter name	Value	Description
uart_baudrate	9600, 19200, 38400, 57600, 115200, 230400, 460800, 921600	RS232#1 baudrate
uart_rxbuf	any, default value is 4096	RX buffer size. We recommend to leave the default value unless you know how to deal with UART RX buffers

read(size=None)

Read data via RS232

Args:

size: number of bytes to receive. Use read() to read all available data.

Return:

Received data

Example to read data:

>>> import sbc
>>> rs232 = sbc.RS232( 115200 )
>>> print(rs232.read(12))
b'Hello World!'

Note

The ouput messages from the RS232#1 are being stored in the RS232 uart_rxbuf buffer.
The default buffer size (4096 bytes) should be enough to read continuously, but be aware that if you don’t read the buffer during a long time, the buffer will be completed and the new messages from RS232#1 will be lost, and by the time you read the buffer you will read “old” messages.
If you want to discard old messages, you can empty the buffer with uart_init() method.

write(data)

Write data via RS232

Args:

data: data to send

Return:

Number of bytes written

Example to write data:

>>> import sbc
>>> rs232 = sbc.RS232( 115200 )
>>> sent_bytes = rs232.write( "Hello World!" )
>>> print('Bytes sent: ', sent_bytes)
Bytes sent:  12

uart_init()

Initializes RS232 UART port

forward_to(uart_fwd=None)

Fordwards RS232 data to a peripheral with UART

Args:

uart_fwd: peripheral object (Gps, XBee)

Example to forward information received on the RS232 socket to GPS1 UART1:

>>> import sbc
>>> rs232 = sbc.RS232( 115200 )
>>> gps1 = sbc.Gps( 1, 115200 )
>>> rs232.forward_to( gps1 )

forward_disable()

Disables RS232 forwarding

get_uart_id()

Get RS232#1 UART port.

Return:

UART port

Note

Since the get_uart_id() method of the RS232 class returns a microPython UART object, it has all its methods.
To do not duplicate the documentation, we suggest to take a look at the official microPython project documentation to see what methods you can additionaly use.

Example of additional methods:

>>> import sbc
>>> rs232 = sbc.RS232( 115200 )
>>> print('There are: ',rs232.any(),' characters to be read')
There are:  1580  characters to be read
>>> print(rs232.get_uart_id().readline())
b'$GNGGA,142222.00,4136.52091,N,00036.70322,E,2,10,1.27,203.6,M,49.8,M,,0000*4D\r\n'