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Domino/SPI/UEXT with ADXL345 accelerometer


#1

I just want to confirm a pin out/wiring for a FEZ Dominio using the UEXT connector and an Analog ADXL345 accelerometer(Sparkfun breakout board) in SPI mode.

ADXL345 UEXT Connector (Domino)
GND 2 (GND)
VCC (3.3V) 1 (3.3V OUT)
CS 10
INT1 4
SDO (SPI OUT) 7 (MISO)
SDA (SPI IN) 8 (MOSI)
SCL 9 (SCK)

Also confirm that the following code is using pin 10 on the UEXT connector for CS (Chip Select)?

_spi = new SPI(new SPI.Configuration((Cpu.Pin)FEZ_Pin.Digital.UEXT10, false, 0, 0, true, true, 100, SPI.SPI_module.SPI2));

The above code was taken from fezzer for a SMB380 accelerometer.


#2

Yes that should work.

You only need to check the SPI timing parameters.


#3

Thanks Joe. My column formatting got alittle screwed up.

When you refer to timing you’re talking about SPI transfer speed (the “100” in the code example I attached)? Or are there other timing parameters to be concerned with? The ADXL345 datasheet gives some idea on the SPI transfer speed relative to the sampling rate of the accelerometer. I’ve been throught the code sample I attached and have a good handle on each arguments.


#4

[quote]_spi = new SPI(new SPI.Configuration((Cpu.Pin)FEZ_Pin.Digital.UEXT10, false, 0, 0, true, true, 100, SPI.SPI_module.SPI2));

The above code was taken from fezzer for a SMB380 accelerometer.
[/quote]

FYI,
The number 100 is not working on SMB380 accelerometer.
It’s supposed to be 200, like this:

_spi = new SPI(new SPI.Configuration((Cpu.Pin)FEZ_Pin.Digital.UEXT10, false, 0, 0, true, true, 200, SPI.SPI_module.SPI2));