Brightsign to HMS 'Synchronous Serial Port' Data Sheet     

This is a software 'Synchronous Serial Port' which I will refer to as 'SSP' in this document.

The SSP clocks out data to the HMS board ( boards with SSP option).  Any number of bytes can be clocked out.  The first byte to clock out controls the outputs of the board (8 outputs).  If the board is equiped with 16 or 24 outputs then byte 2 controls outputs 9-16 and byte 3 controls outputs 17-24.

For boards with DMX output, the first byte will control the first 8 outputs of that board.  If there are 16 outputs, then the second byte will control outputs 9-16, and if there are 24 outputs, the third byte will control outputs 17-24.  The rest of the bytes will be sent to the DMX channels.

SSP software: Note: SSP pins 'MR' and 'CLK' are normally high

3 pins are utilized for SSP.  'MR' (serial port 'Master Reset'), CLK (serial port clock), and SDO (serial data out).

• MR  [Btn7]: To reset the serial receiver on the HMS board, set this pin low then high.  The low to high transistion of this pin is detected by the HMS board and the board resets the receive count and resets the serial port so that the next clock transition clocks in the first bit of the first byte to be received.
• CLK [Btn6]: The 'CLK' bit set low then high triggers the SSP port on the HMS board to clock in the bit on the 'SDO' line.
• SDO [Btn5]: 'Serial Data Out'.  This pin has to be set high or low prior to the CLK signal going low then high.  The most significant bit of the byte is clocked out first.

If the Roku Script follows this 'outline' then there will be no timing issues.  The 'data byte' is the 8 bit byte to be sent to the HMS board using the SSP software as defined below..

SSP Software Flow:

1. Call the routine 'set_MR_low'. (set MR low).
2. Call the routine 'set MR high'. (set MR high)
3. Set bit SDO to high or low depending on bit 7 of the 'data byte'
4. Call the routine 'clock it'. (set the CLK low then high).
5. Set the SDO high or low depending on the bit 6 of the data byte. 
6. Call the routine 'clock it'. (set the CLK low then high).
7. Set the SDO high or low depending on the bit 5 of the data byte. 
8. Call the routine 'clock it'. (set the CLK low then high).
9. Set the SDO high or low depending on the bit 4 of the data byte. 
10. Call the routine 'clock it'. (set the CLK low then high).
11. Set the SDO high or low depending on the bit 3 of the data byte. 
12. Call the routine 'clock it'. (set the CLK low then high).
13. Set the SDO high or low depending on the bit 2 of the data byte. 
14. Call the routine 'clock it'. (set the CLK low then high).
15. Set the SDO high or low depending on the bit 1 of the data byte. 
16. Call the routine 'clock it'. (set the CLK low then high).
17. Set the SDO high or low depending on the bit 0 of the data byte. 
18. Call the routine 'clock it'. (set the CLK low then high).

To send out any subsequent bytes repeat steps 3-18.  In theory, the limit to the number of bytes is should be 512 + output bytes. If the board has two 8 bit output sets (16 outputs) then the output bytes would be 2.  If the board has only a single 8 bit output set, then the 'output bytes' would be 1.  It is very unlikely that you would want to control 512 DMX channels using the Brightsign.  So, for now, the number of DMX bytes will be limited to 16.  The 16 bytes will allow for control of up to four '4 channel' dimmer packs.  This should be adequate for the Brightsign use.

See the 'About DMX' page for more information on DMX512.

Link: A link to the SSP script will be provided as soon as the script is completed.  There will be plenty of documentation in the 'script file' to make it easy to use.

Note: Custom software available to meet your special lighting requirement.  Any number of DMX channels can be programmed per your requirement.

Updated: September 25, 2009