Hardware Reference
In-Depth Information
Figure 10-4.
SABB connection diagram (note the pull-down resistors)
When loading the code to each board, be sure to assign a unique address to each. No other changes need to be
made to the code. Finally, connect to at least one of the boards through a serial terminal. From this point, you can
send a string to the board. This string will be sent to any devices connected on the bus. The first byte will be examined
for a matching address, and if a match occurs, that device will echo the data it receives. Both the data sent and the
data received will be displayed from the sending device. Also, the code is set to change the state of an LED whenever it
is addressed in a communication sequence. This provides two ways to demonstrate a successful transfer.
After the code is verified, add another Arduino if possible; you can do this on the fly, as functionality for hot-swap
is included in this code example.
Connecting SABB to SPI
While this example does not demonstrate communicating to a conventional SPI device, this is possible, and one can
be added. Since the SPI block will remain idle when not activated by the chip-select line going low, conventional
SPI devices can share the same bus lanes as SABB. You can make a device running SABB a master in an SPI network
by following proper procedure. Figure
10-5
shows a block diagram demonstrating one connection possibility of SPI
sharing a SABB data bus. This relation between SABB and standard SPI allows for every SABB-enabled device to share
standard SPI devices if the SS lines are connected to each SABB device that requires the resource.
