Data Sheet

dScript

dScript User Manual v2.15

Serial ports

dScript Modules may implement one or more serial ports, these are declared at the start of

your program. Because it takes time to send data out over a serial port we provide each port

with both receive and transmit FIFO (first in first out) buffers. Once declared a serial port will

receive and transmit in the background. Received data will be placed in the Rx Fifo ready for

when your program wants to fetch it. Transmit data can be sent to the Tx Fifo and will then be

sent out in the background. You decide how big these Fifo buffers are, up to the limit of

available RAM. The default format for a newly declared serial port is 9600 baud 2 stop bits.

serialport Name PortNumber RxFifoSize TxFifoSize

serialport LCD05 1 10 90

Name

The first parameter is the port name. This is the name you will use to refer to this serial port in

the rest of your program. In the above example we will connect an LCD05 display module, so

naming the port LCD05 provides a descriptive name to make the program more readable.

PortNumber

Some modules may have three serial ports numbered 1, 2 and 3. This selects which physical

port to use.

RxFifoSize

This is the size of the receive or Rx FIFO. Here the LCD05 will only ever send a few bytes back

in response to a command, so 10 bytes is plenty.

TxFifoSize

This is the size of the transmit or Tx FIFO. In the case of the LCD05 which is a 20x4 character

display, we want to send a complete screen of data plus a few control codes as well, so the size

is set to 90 bytes.

The above example names serial port 1 as "LCD05" with an Rx buffer size of 10 bytes and a

transmit buffer size of 90 bytes.

Writing data to a serial port

The "Write" command is used to send serial data. The syntax is:

mySerialPortName.Write( <string name>, <start position>, <number of bytes to send>)

Data to be written to the serial port should be placed into a string - think of it as a byte array

of the data to send.