Sensor Hub Booster Pack compatibility with Tiva Connected Launchpad?

Hi Amit,

I was a little bit afraid to power up the Tiva Connected Launchpad connected with Sensor Hub as, I thought the +5V of Tiva Connected Launchpad would make problems with Sensor Hub. But, upon further confirmation the +5V of Tiva Connected Launchpad has no connections with Sensor Hub Booster Pack.

Also, I got confused with I2C7, as it can be assigned to two GPIO pins. I am only familiar with 1 gpio pin with 1 or more several alternate function.

Amit Ashara said:

The X6 and X8 header is for the SensorHub Booster Pack as shown in the schematic

I am just testing the temperature sensor, since I am trying out the "temperature_tmp006" example program. From further verification the relevant header is X9 for booster pack 1 and X7 for booster pack 2.

So, the relevant connections are the 3.3V, GND, I2CSCL, I2CSDA and INT TEMP. The INT TEMP of Sensor Hub Booster Pack is connected to PH2 of Tiva Connected Launchpad. See, pic below. Only the right most side of the table has the relevant pins. This is the pin connection of Sensor Hub to Tiva Connected Launchpad Booster Pack 1 connector.

Amit Ashara said:

R19 and R20 need to be populated as per the instructions in the schematics for I2C to work

This is for booster pack header 2. Since the temperature_tmp006 example program was made for booster pack connector 1, your suggestion does not apply. But, I will still need to put pull-up resistors at the corresponding I2C pins at booster pack connector 1, as there are none indicated at schematic of both Tiva Connected Launchpad and Sensor Hub Booster Pack. 

So, I tried to debug the temperature_tmp006 example program and the welcome message is not printed out at Tera Term. I will put the pull up resistors at I2C pins of Tiva Connected Launchpad and try to debug again at a later time.

//
// Print the welcome message to the terminal.
//
UARTprintf("\033[2J\033[1;1HTMP006 Example\n");

- kel

Hello Kel

That should not be the case. I have once had a similar issue but all prints before I2C worked.

The only thing I could think of is that a CPU reset did not reset the NVIC and a previous interrupt got asserted causing the CPU to loop. Is it possible or you to revert the 10K change and see where the CPU is stuck?

Regards

Amit

@Amit,

    I have confirmed now that without the pull-up resistors at I2CSCL and I2CSDA, the welcome message and temperature values are being printed out at Tera Term. I don't know at that time a day ago why, there is no print out at Tera Term.

   I don't have much extensive experience with I2C. But, I know the pull-up resistors is necessary at I2C lines. Now, it confuses me why it works without the pull-up resistors. I will research more on that.

-kel

Hi,

   So what happened was the two pull-up resistors at I2CSCL and I2CSDA is connected to 3.3V. When, I lift the connection at 3.3V, now there is a 10K resistor + 10K resistor across I2CSCL and I2CSDA. At this condition there is still output at Tera Term.

  But, when I removed the two 10 K resistors at the board, there is no output at Tera Term.

- kel

With or without those "missing/magical" pull-ups - does not the, 34.34 "ambient temperature" cause concern? 

Such may be a suitable indoor temperature (if in °F) - for an igloo - in Alaska.  For your (Philippines) location (and reading °C) - I'd investigate use of a BLDC motor to, "Crank up" your AC...

Disagreement as regards the correct headers tends to challenge the (self-awarded {always suspect}) Verify...

Hello Kel,

I tried the same experiment with the Pull Up's on I2C removed and it prints the welcome message every time. You may want to debug the issue using step debug.

Regards

Amit

cb1_mobile said:

does not the, 34.34 "ambient temperature" cause concern?

34.34 Celsius is normal where my computer room is at my house at that time. If I want a free sauna I just stay at my room when the sun is high up in the sky. But, I don't do that. 

@Amit.

Having more time, I have finally confirmed that the sensor hub examples at the sensor hub library works with the pull-up resistors and without the pull-up resistors at I2C lines. I confirmed several times.

The welcome message and the values are all printed out at Tera Term. I have also tested while debugging at Keil Uvision. But, my concern is isn't that the pull-up resistors necessary at I2C lines? I don't see any pull-up resistors at I2C lines at both schematic of Sensor Hub and Tiva Connected Launchpad. But, at the moment I am happy with these results. 

Here is the picture below of the Tiva Connected Launchpad + Sensor Hub with the pull up resistors at I2CSCL and I2CSDA. 

You can all see how I expertly placed the pull-up resistors at the I2C lines. (That is a joke)

I verified the connections using DMM Connectivity test. 

- kel

@Amit,

    I verified also the pull-up resistors at the schematic of Sensor Hub. It is at the bottom part. Thanks !

Edited. .

   As summary, the Sensor Hub Booster Pack is pin compatible with Tiva Connected Launchpad. Sensor lib examples are set-up by default to interface Sensor Hub Booster Pack at Tiva Connected Launchpad Booster Pack 1 Connector.

   As mentioned at the code comments of the Sensor Lib examples, you need to modify the Sensor Lib example initialization to make the Sensor Hub work with Tiva Connected Launchpad Booster Pack 2 Connector.

   There is no need to put pull-up resistors at I2C lines as there are already 3.3K Ohm pull-up resistors at the I2C lines of the Sensor Hub Booster Pack.

-kel

Schematic diagram - as introduced by Amit - seems definitive. 

Classic means to monitor for the presence of such pull-up Rs is via DMM attached to each I2C line.  Each should "pull" to near 3V3 - if the resistor is present.  When board is unpowered - and provided such DMM does not provide in excess of 5V when in "k-ohms" mode - the resistance (between 3V3 and each I2C line) may be measured/confirmed.

At times - it may be that oxidation has arrived at one/several of your interconnects - which may cause erratic operation.  Cure here is to, "seat/unseat" such, "board to board" interconnects several times.  (the contact "wiping" tends to reestablish the designer's connection intent...)

34° inside/room temperature may "bring about" those "sleep periods" your posts sometimes note... (along w/consumption of adult beverages - past reported/noted - I'm told...)