Copyright © 2015 Robot Circuits, LLC
20
RCAT-1A Rev A3 Designer’s manual
Serious Power for the Serious Designer
The example software solution provided with your RCAT™ includes code to read this device and calculate pitch
and roll information. Of course, much more complex data manipulation is possible (see the Analog Devices
datasheet for details), but this example will provide you with the basic methods for reading and writing the
various registers on the device.
Like the EEProm, the accelerometer is hung on the TWI system so that you could control it externally is desired.
Referring to the schematic under the TWI section above you see two jumpers associated with this device.
Jumper JP23 determines the address at which the accelerometer is configured:
Position
Write addr
Read addr
A-B
0x3A
0x3B
B-C
0xA6
0xA7
Table 3
The accelerometer features two interrupt outputs that are actuated in response to certain events inside the
chip. These interrupt outputs are sent to the CPU on PE4 and PE5 as shown in the schematic in the TWI section
above. In addition these interrupts are broken out to connector J5 on positions PE4 and PE5 for monitoring by
your external hardware.
SPI Interface
CPU ports PB1, PB2 and PB3 are brought out to connector J1 as shown below:
Schematic
Figure 15
As shown, access to the CPU /RST pin as well as Vcc and Gnd are also provided. J1 is laid-out to allow easy
connection to programming devices that utilize Serial Peripheral Interface (SPI). If not utilizing the SPI system,
these CPU ports are available for general purpose use.
