Using the Grapevine^Ó 24 LED Universal Driver Board

The latest Grapevine^Ó Universal Driver Board can drive up to 24 bicolor LEDs and up to 8 slow motion switch machine motors. This expands to 96 the total number of LEDs that a single Grapevine^Ó Node can address. In addition, the new Driver Board requires a filtered supply voltage of between 10 and 12 VDC. The 24 LED Universal Driver Board requires Grapevine^Ó Node software Version 5 or above. The latest driver board uses microcontrollers to drive the LEDs and switch machine motors. This allows additional features to be programmed into the driver.

The Grapevine^Ó Universal Driver Board is shown in the photograph below.

The driver board is connected to the Grapevine^Ó Node through the 4-pin header at the top left hand corner of the board. Two 6-pin programming headers are shown at the top of the board that permit field programming of future features. LEDs are connected to the 12, 3-pin headers in the center of the board. The LED driver outputs are grouped in pairs as shown in the photograph. The numbered header pins are connected to the green anode of a bicolor LED. The third pin at the bottom of the 3-pin header is the common pin for each pair of signals. This supplies 2.5 VDC to the red anode of each bicolor LED. All of these pins are electrically connected on the board. (Note: This common pin is not at ground voltage. Do not connect these pins to ground – irretrievable damage to the board will result.)

Slow motion switch machines are connected to the 8, 2-pin connectors at the bottom of the board. The numbering of the switch machine outputs is shown in the photograph. The LED drivers and the switch machine drivers occupy the same logical addresses as shown in the numbering scheme. For example, a command sent to output 1 affects both the LED driver and the switch machine driver. This means that in general you would not use the LED driver output and the switch machine driver output at the same time. Please note the following important feature: When the board is first powered up, the switch machine driver outputs will be off. Sending a “normal” or “reverse” command to output 1 turns on switch machines 1, 2, 7 and 8. Likewise, sending a “normal” or “reverse” command to output 13 turns on switch machines 13, 14, 19 and 20. The switch machines can also be turned off in a similar manner: Sending an “off” command to output 1 turns off switch machines 1, 2, 7 and 8 and command to output 13 turns off switch machines 13, 14, 19 and 20.

Note to Programmers

In previous Grapevine^Ó Node software versions 4 driver boards of 12 outputs each could be driven. Programmatically these were Banks 0 to 3. In order to expand the address space available on the Grapevine^Ó Node for signal outputs while maintaining compatibility with the old driver boards a new command was introduced. This is the “Bank Shift” command, and is Bank 1, Command 122. When you wish to address LED driver outputs 12 to 24, you must precede the signal data with this command. It had the normal 4 byte structure:

Address 122 address Bank + parity

For example using node address 99 as an example, the four bytes are:

128+99 122 128+99 1*16+3 or 227 122 227 19.

This is followed by the normal signal data command. Note that this means that signal outputs 13 to 24 are addressed as signal outputs 1 to 12 preceded with the Bank Shift command.