4.5.10. Serial port¶
Controller allows control through UART serial port with TTL 3.3 V logic. UART outputs are located on BPC connector. Because of widespread availability of UART and adapters to USB, Bluetooth, Ethernet and other standard interfaces there is an option for wireless control (Bluetooth) or control over the internet (Ethernet). UART data protocol is the same as USB data protocol. I.e. it is enough to enable nonstandard serial port polling in XiLab or in libximc and the device will be found if response delay doesn't exceed two seconds. It is also possible to control controller with the help of other independently programmed micro-controller, however in this case it will be required to support controller communication protocol.
UART supports the following settings.
|Transfer rate||9600-921600 bit/sec|
|Parity||enabled or disabled|
|Parity type||even, odd, space, mark|
|Stop bits||1 or 2|
Note. To connect to the controller via UART one should first connect to it via USB and set required speed, parity and stop bits and then save settings to non-volatile memory. Standard settings are listed in Communication protocol specification, use them if you cannot connect.
|Logic type||TTL 3.3V|
|Maximum data transfer speed||921 kbit|
|Nominal output current||5 mA|
Output and input parameters
WARNING. High data transfer speeds through long cables in case of electromagnetic interference are impossible. If transfer errors do occur, use RC filtering circuits and reduce transfer speeds so that characteristic time of an RC-circuit is at least 4 times less than time needed to transfer a single bit. RC-circuit characteristic time is chosen based on the circumstances.
Recommended scheme of connection to serial port pins for the controller board
One-axis and two-axis systems¶
Recommended scheme of connection to serial port pins for two-axis system