About POLARITY   (USB or TTL-Serial)

HMS has recently built in 'Serial Polarity Detection' into the firmware of the USB-S3-xxxx boards (February 2024).  The reason for this change is to eliminate the requirement of a BrightSign to have 'invert serial signals' as a setup requirement when using the TTL serial port of the BrightSign.  This 'Auto-POL' software requires a slight change to your BrightAuthor file.  In the beginning of your program you need to synchronize the Brightsign to the HMS Board.  This is because the BrightSign only enalbles power to the USB port after several seconds after power is applied.  Because of this the board configures itself to the TTL serial port because the serial pins are low with no USB power as the HMS board initializes.  This is the wrong polarity for USB.

To synchronize the BrightSign to the HMS board you need to send a null byte followed by a 21 millisecond delay.  So in your code you should have a 'send serial bytes, comma seperated' command followed by a pause of 21 milliseconds.  A single serial byte of 0 is all that is needed to sync the HMS board.  The 21 millisecond pause resets the receive pointer of the HMS board back to zero (waiting for the first command byte or port byte)

Note: If you require boards without polarity detection let us know.  You can add a comment to your order 'No Polarity' or email the store manager with this request after you place the 'PayPal' order.

Last Revised: 02/19/2024