Combination of BMP085 and ATAVRSBIN1 not working

[crashlander]

Hello,
if I combine BMP085 (Sparkfun 3V version or Ebay 3-5V version) and ATAVRSBIN1 I get uncountable I2C errors and no response from baro.
Without baro ATAVRSBIN1 works O.K. (0 I2C errors)
Combination of BMP085 + WMP + MMA7455 also works (so it is not faulty baro).
I'm using external 2.2k pull-ups (5V sourced) and disabled internal ones (//#define INTERNAL_I2C_PULLUPS)
For 3.3V version I'm using 3.3V output from ArduinoMega and Sparkfun's LLC (BOB.. something).
Combination 2 BMP085 (Ebay) + WMP + MMA7455 is full 5V.

Best Regards
Andrej.

[vistauser]

Hi Andrej,

I´m using BMP085 and ATAVRSBIN1 on a Paris v4.0 board and this combination is working fine
with MULTIWII SW 2.0pre4. Height hold and heading hold is satisfying with default settings.

mfg
vistauser

[PatrikE]

Mine don't work without.
#define INTERNAL_I2C_PULLUPS

[crashlander]

Mine don't work without.
#define INTERNAL_I2C_PULLUPS

If I understand correctly you have external pull-ups and defined INTERNAL_I2C_PULLUPS?!

Regard Andrej

[PatrikE]

If I understand correctly you have external pull-ups and defined INTERNAL_I2C_PULLUPS?!

Yepp...
But i dont remember the value on the ressisors i use..

If It works don't touch it...

[crashlander]

If I understand correctly you have external pull-ups and defined INTERNAL_I2C_PULLUPS?!

Yepp...
But i dont remember the value on the ressisors i use..

If It works don't touch it...

Do you remember how it failed?
I get fast increasing I2C errors and altitude stops at aprox. -312m (always).
I'm running at 400kHz (but it didn't work also at 100kHz).
My pull-ups are on 5V arduino side of LLC.

[aBUGSworstnightmare]

Hi crashlander,

sounds like your pull-ups were a little to weak!

1.) disable the internal pull-ups when you have external pull-ups on the 5V side of the LLC. The pull-ups should be 2.2kOhm to 4.7kOhm

2.) I assume you also have 3.3V pull-ups on the LLC, right? In addition, there are some pull-ups on the ATAVRSBIN1 and maybe also a set on your BMP085 breakout.
Can you pls provide more details on the LLC you're suing and on the BMP085 breakout?

You need to ensure that your pull-ups were 2.2kOhm to 4.7kOhm when you want to run the I2C-bus at 400kHz

Details on an ideal carrier board for the ATAVRSBIN1 were here: viewtopic.php?f=6&t=1297

Rgds
aBUGSworstnightmare

[crashlander]

Hi crashlander,
sounds like your pull-ups were a little to weak!

1.) disable the internal pull-ups when you have external pull-ups on the 5V side of the LLC. The pull-ups should be 2.2kOhm to 4.7kOhm

I'm using 2.2k pull-ups on 5V side, and disabled internal ones.

2.) I assume you also have 3.3V pull-ups on the LLC, right? In addition, there are some pull-ups on the ATAVRSBIN1 and maybe also a set on your BMP085 breakout.
Can you pls provide more details on the LLC you're suing and on the BMP085 breakout?

From schematics it seems it has 10k pull-ups on LLC on both sides (5V and 3.3V)
http://www.sparkfun.com/datasheets/Brea ... er-v10.pdf
And BMP085 3.3V version has 4.7k pull-ups on board but it doesn't work with or when removed.
http://dlnmh9ip6v2uc.cloudfront.net/dat ... ut-v11.pdf

You need to ensure that your pull-ups were 2.2kOhm to 4.7kOhm when you want to run the I2C-bus at 400kHz
aBUGSworstnightmare

Like I said ATAVRSBIN1 alone runs with zero I2C at 400kHz.