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Linux/MSP430I2040: MSP430I2040 Linux Host processor SDK, calibration & Isolation circuits

Ravikumar Gaddam
Prodigy 20 points
Part Number: MSP430I2040
Other Parts Discussed in Thread: TIDM-TWOPHASEMETER-I2040, EVM430-I2040S

Tool/software: Linux

Hi,

I am working on MSP430I2040 EVM kit. EVM support windows environment, and its working fine.

But I have to write an application on Host Processor(ARM with linux).

1. Is there any standard SDK & Documents?

2. To PC, connected serial cable after isolation circuit. Should I connect UART directly to Host processor without Isolation circuit?

3. MSP430I2040 supporting I2C. i want to communicate MSP430I2040 via i2c instead of UART. Is it Possible and please point SDK folder? Is i2c required Isolation circuit?

4. Is there any proper documentation for calibration command.?

Thanks in advance.

Ravikumar.G

  • 0
    TI__Mastermind 49692 points

    Hello Ravikumar,

    Ravikumar Gaddam said:

    But I have to write an application on Host Processor(ARM with linux).

    1. Is there any standard SDK & Documents?

    I'm not sure. This depends on the Host Processor that you've chosen. If you're asking about an SDK for the i20xx device, we do not provide a SDK, only the Energy Library code.

    Ravikumar Gaddam said:
    2. To PC, connected serial cable after isolation circuit. Should I connect UART directly to Host processor without Isolation circuit?

    The isolation circuitry on the UART interface protects your PC (and probably you) from being damaged by the High Voltage applied to the EVM (system) and allows you to read data from the device. Let's assume that your system is isolated and will transmit the data via wireless communication. Then, it should be safe to say that you don't need isolation circuitry between the i20xx device and the Host Processor. Depending on your application, you may need isolation in other areas of your design. This is very important to ensure that the user or operating environment is safe from the High Voltage.

    Ravikumar Gaddam said:
    3. MSP430I2040 supporting I2C. i want to communicate MSP430I2040 via i2c instead of UART. Is it Possible and please point SDK folder? Is i2c required Isolation circuit?

    I'd recommend that you look through the code examples for the i20xx and search for an I2C example(s). Regarding isolation, see my comments above to determine if you need the isolation on the I2C interface. In the Energy Library code that's provided for the EVM, you'll have to reconfigure the pins for I2C operation, etc., and change the protocol in the 'emeter-communication.c', 'emeter-dlt645.c' files (and probably more).

    Ravikumar Gaddam said:
    4. Is there any proper documentation for calibration command.?

    For getting started with calibration, I would recommend that you use the GUI to calibrate the board and record the new calibration factors for your custom board. You may be looking for the "HOST_CMD_SET_CALIBRATION_PHASE_N" command (described here), which you could use with the Host Processor to change the calibration factors.

    Regards,

    James

    MSP Customer Applications

  • 0 in reply to James Evans
    Prodigy 20 points

    Thanks for information,

    So, i will connect  3.3V and GND to j5 jumper and UART to J6 jumper from Host CPU board with out Isolation!!!!

    Have compiled calibrator application code without UI on Linux and its working fine (tested with RS232 connector).

    Anything i have to take care?

  • 0 in reply to Ravikumar Gaddam
    TI__Mastermind 49692 points

    Hello,

    To be safe, I would recommend using isolators between the Linux host and the i20xx device. Like I mentioned above, there are certain scenarios where you don't have to do this, such as when there's no wired connection from the host processor to another device (e.g. Ethernet, USB, etc.) and when Current Transformers (CT's) are used. Shunts typically require isolators. I looked at our TIDM-TWOPHASEMETER-I2040 TI Design, and the interface between the host and i20xx device is isolated because there's a USB interface on the host, which would connect to a PC. The isolators would protect the PC and ultimately the user. The TIDM-TWOPHASEMETER-I2040 design uses ISO722xA isolators, but I'm assuming we offer newer, improved isolators today.

    I'm sorry if I seem like I'm giving you two different answers. If there are any doubts when using High Voltage, it's always safer to use isolation.

    Assuming that you're using the EVM430-I2040S board, are you planning to power this board from the High Voltage using the on-board power supply? If so, you'll want to keep the jumpers across J5. The silkscreen on the PCB should show which orientation, but you can double-check Figure 10 and the schematic in the User's Guide to be sure. If you are NOT using High Voltage and are planning to power up the EVM using an external power supply for debugging, I'd remove the jumpers on J5 and apply 3.3V and GND to the right-most pins.

    For the UART connection, you can use Pin 1 (TXD) and Pin 6 (RXD) on the J6 header.

    Hopefully this helps.

    Regards,

    James

    MSP Customer Applications

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