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DLP3010EVM-LC: I2C Communication with external MSP430

Faheem Quazi
Prodigy 40 points
Part Number: DLP3010EVM-LC
Other Parts Discussed in Thread: MSP430FR5969, MSP430WARE

Hello!

I have a DLP3010EVM-LC, and an MSP430FR5969 Launchpad. I am attempting to send commands to the DLPC via I2C using the J14 Connector; Per my requirements, I can't use/program the MSP430 onboard the Eval kit for anything, so it remains untouched.

I have it wired as follows:
J14 - Headers soldered on
Pin 1 - Connected to P1.6 (Pulled up to VCC via 10k resistor; tried with and without this)
Pin 2 - Connected to P1.7 (Pulled up to VCC via 10k resistor; tried with and without this)
Pin 3 - Connected to GND
Pin 4 - Connected to VCC

On the MSP430FR5969, I am using the EUSCI_B_I2C_* calls to send the commands. I copied the initialization code and most of the logic from MSP430Ware "Driver Library" examples in the Resource Explorer; however I am not using interrupts as some of the tx examples do.

It appears that the DLPC is not responding to any commands sent through this connector. When it is connected, the onboard buttons also do not respond (with and without pull-up resistors). I'm WFH Intern and working on getting a logic analyzer to check the I2C bus but at the moment I can't see why it isn't working.

Your guidance is appreciated, I can post more details as you need them. I'm pretty new to this world so I apologize if I use incorrect terms.

  • 0
    TI__Genius 12595 points

    Hi Faheem,

    Welcome to the E2E forum! I'm happy to look into this for you.

    Can you tell me more about what you mean by saying that the DLPC is not responding? How are you reading the output signals?

    Regards,

    Austin

  • 0
    TI__Genius 12595 points

    Hi Faheem,

    When you describe the pin connections for pins 1-4, are these the JTAG pins (J1) on the EVM's main board?

    Regards,

    Austin 

  • 0 in reply to Austin Snyder
    Prodigy 40 points

    Hello Austin,

    To answer both your questions:

    1. I'm working on getting a Logic Analyzer to actually read those output signals, but basically when I connect the pins as indicated, the onboard buttons no longer respond and my MSP430 hangs on waiting for an ACK from the slave 0x37 (at least from what I can tell).

    2. These are pins 1-4 on the "Connector for the I2C interface" (J14) on the EVM Main Board. I soldered headers onto the connector in order to connect it to the MSP430 via jumper wires. I got the pin assignments from the design files for the main board.

    Hope this helps,

    Faheem

  • 0 in reply to Faheem Quazi
    TI__Mastermind 28005 points

    Faheem,

    Have you checked whether the MSP430 on the EVM itself is displaying any activity? If the two MSP430s are both attempting to communicate at the same time you may introduce I2C bus hangups.

    What does the scope capture look like?

  • 0 in reply to Philippe Dollo
    TI__Mastermind 22840 points

    Hello Faheem,

    Do you still need assistance with this issue?

    regards,

    Vivek

  • 0 in reply to Vivek Thakur
    Prodigy 40 points

    Apologies for the delay, I was temporarily assigned a different project with a short turnaround. I will promptly answer your questions early next week when I'm back on this task.

    Thank you for your patience.

    Faheem

  • 0 in reply to Faheem Quazi
    TI__Genius 9971 points

    Faheem,

    Thanks for the update, we will wait for you to come back.

    Regards,

    Mayank

  • 0 in reply to Philippe Dollo
    Prodigy 40 points

    Philippe Dollo said:

    Faheem,

    Have you checked whether the MSP430 on the EVM itself is displaying any activity? If the two MSP430s are both attempting to communicate at the same time you may introduce I2C bus hangups.

    What does the scope capture look like?

    Just checked this. It appears that the onboard MSP430 is almost constantly communicating with something on the board; not completely sure yet, but it's some kind of heartbeat that happens consistently every half-second to a second. I was provided one of those Sparkfun Logic Analyzers and I determined that the onboard MSP430 does constantly hold the I2C lines, which is probably why writing to the bus results in nothing. I did disconnect my MSP430 and directly connect it to the analyzer and verified that at least the initial address + read command is being produced correctly and identically to the onboard MSP430. From that, I concluded that I probably need to disable the onboard MSP430 if I want to mess with it externally. 

    Appreciate the help from all; unfortunately my tour is coming to a close so I probably won't be able to proceed further than that. At the very least, I can code something that appears to work from the perspective of the scope :) If you have any additional feedback, I can forward that to my team.