Terasic De0-Nano, User Manual

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The ADXL345 is a small, thin, ultralow power, 3-axis accelerometer with high resolution
measurement. This digital accelerometer can be accessed through a SPI 3-wire digital interface or
I2C 2-wire digital interface. Main applications include medical instrumentation, industrial
instrumentation, personal electronic aid and hard disk drive protection etc. Some of the key features
of this device are listed below. For more detailed information, please refer to its datasheet which is
available on manufacturer’s website or under the /datasheet folder of the system CD.

Up to 13-bit resolution at +/- 16g

SPI (3- wire) or I2C (2-wire) digital interface

Flexible interrupts modes
Figure 3-13 shows the connections between the ADXL345 and the Cyclone IV E device.
Figure 3-13 Wiring between the ADXL345 and the Cyclone IV E device
Table 3-10 Pin Assignments for Digital Accelerometer
Signal Name FPGA Pin No. Description I/O Standard
I2C_SCLK PIN_F2 EEPROM clock 3.3V
I2C_SDAT PIN_F1 EEPROM data 3.3V
G_SENSOR_INT PIN_M2 G_Sensor Interrupt 3.3V
G_SENSOR_CS_N PIN_G5 G_Sensor chip select 3.3V
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The DE0-Nano board includes a 50 MHz oscillator. The oscillator is connected directly to a
dedicated clock input pin of the Cyclone IV E FPGA. The 50MHz clock input can be used as a
source clock to drive the phase lock loops (PLL) circuit. The clock distribution on the DE0-Nano
board is shown in
Figure 3-14 .