baud = uart.setup( id, baud, databits, parity, stopbits )

Setup the serial port

Arguments:

• id - the ID of the serial port
• baud - serial baud rate
• databits - number of data bits
• parity - parity type, can be either uart.PAR_EVEN, uart.PAR_ODD or uart.PAR_NONE
• stopbits - the number of stop bits, can be either uart.STOP_1 (for 1 stop bit), uart.STOP_1_5 (for 1.5 stop bits) or uart.STOP_2 (for 2 stop bits)

Returns: The actual baud rate set on the serial port. Depending on the hardware, this might have a different value than the baud parameter

uart.write( id, data1, [data2], ..., [datan] )

Write one or more strings or numbers to the serial port. If writing a number, its value must be between 0 and 255.

Arguments:

• id - the ID of the serial port.
• data1 - the first string/number to write.
• data2 (optional) - the second string/number to write.
• datan (optional) - the n-th string/number to write.

Returns: nothing.

str = uart.getchar( id, [timeout], [timer_id] )

Read a single character from the serial port

Arguments:

• id - the ID of the serial port
• timeout (optional) - timeout of the receive operation, can be either uart.NO_TIMEOUT or 0 for non-blocking operation, uart.INF_TIMEOUT for blocking operation, or a positive number that specifies the timeout in microseconds (in this case, the timer_id parameter is also required). The default value of this argument is uart.INF_TIMEOUT
• timer_id (optional) - the ID of the timer for the receive operation, needed if the timeout parameter specifies an actual timeout (that is, timeout is neither uart.NO_TIMEOUT, nor uart.INF_TIMEOUT).

Returns: The character read from the serial port as a string, or the empty string it timeout occured while waiting for the character.

str = uart.read( id, format, [timeout], [timer_id] )

Reads one or more characters from the serial port according to a format specifier

Arguments:

• id - the ID of the serial port
• format - format of data to read. This can be either:
  • '*l' - read until an end of line character (a \n) is found (the \n is not returned) or a timeout occurs.
  • '*n' - read an integer. The integer can optionally have a sign. Reading continues until the first non-digit character is detected or a timeout occurs. This is the only case in which read returns a number instead of an integer.
  • '*s' - read until a spacing character (like a space or a TAB) is found (the spacing character is not returned) or a timeout occurs.
  • a positive number - read at most this many characters before returning (reading can stop earlier if a timeout occurs).
• timeout (optional) - timeout of the receive operation, can be either uart.NO_TIMEOUT or 0 for non-blocking operation, uart.INF_TIMEOUT for blocking operation, or a positive number that specifies the inter-char timeout in microseconds (in this case, the timer_id parameter is also required). The default value of this argument is uart.INF_TIMEOUT
• timer_id (optional) - the ID of the timer for the receive operation, needed if the timeout parameter specifies an actual timeout (that is, timeout is neither uart.NO_TIMEOUT, nor uart.INF_TIMEOUT).

Returns: The data read from the serial port as a string (or as a number if format is '*n'). If a timeout occures, only the data read before the timeout is returned. If the function times out while trying to read the first character, the empty string is returned