adxl345 problem reading registers

Even before sensing acceleration, I like to talk
to a sensor I am using. So I am trying to read some of
the 30 registers. I can read the sensor id register 0x00
but the rest of them are all one's (%11111111).
My question is: am I just reading the RESET values.
Or do I have to WRITE something first to enable me
to do a real READ of the REGISTERS ?
 

AllyCat

Senior Member
Hi,

I've never used that chip, but the first obvious questions from a quick scan of the data sheet: Are you using the SPI or I2C bus, how is /CE driven and what address/register values have you tried? Posting your test program and/or schematic diagram might be helpful.

Cheers, Alan.
 
I'm using the sparkfun breakout. I'm using I2C.
I was wondering whether the CE wanted a hi or lo
select.I'm looking at the first 8 or so regs
and was surprised a lot of addresses nearby were RESERVED.
I'm running a 14m2 at 3 v. I'll post a schematic and some of the code
a little later.
 

AllyCat

Senior Member
Hi,

The manual says that /CE must be High to use I2C mode, and the I2C address is $3A (or $A6 if pin 12 is grounded). It also says that addresses 1 - 28 are reserved and "Do not access", then 29 to 57 (decimal) should mainly return zero (except 44 and 48).

Cheers, Alan.
 
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