Bascom ADXL345 via I²C -no response by device

autoguider · Joined: 24 Sep 2007 Posts: 82 Location: Aachen

Dear all,
I do my first steps with I²C on Bascom so it may be that I do not see the trees because of the forest.
I want to run a ADXL345 accelerometer via I²C.
The accelerometer is on a breakout board installed on a breadboard. MCU runs on Arduino UNO R3 board.
SCA,SCL are pulled HIGH to VDD=5V via 2k4 resistors.
SDO , which to my opinion is the AltAddress pin is fixed to VDD.

This has now influence on the codes for reading and writing to registers.

As I understand the datasheet the 7 bit slave address is 0011101.
To complete it to a byte the LSBit is attached to the right hand side. 1 for read ; 0 for write
So the command after the start announcing a writing access is 00111010 (3A)
So the command after the start announcing a reading access is 00111011 (3B)

I also integrated a bus scanner in the program.
No slave is found by the scan.

The code is attached.

Please be so kind to give me some advice.

Best regards
Christian

(BASCOM-AVR version : 2.0.8.1 , Latest : 2.0.8.2 )

MWS · Joined: 22 Aug 2009 Posts: 2335

There are some hits doing a forum search for ADXL345.

i.dobson · Posted: Fri Sep 27, 2019 7:47 pm Post subject:

Hi,

I've had a quick look at your code and I can't see where you configure and initalise the i2c bus.

You Need to include something like this to Setup the i2c bus before you use it: