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Minimum board requirements for TMDSEVM6657 DSP

ahmed helal59
Intellectual 270 points
Other Parts Discussed in Thread: TMS320C6657

Hello,

I'm planning to buy TMDSEVM6657LS multicore DSP board to interface it with i2c/spi sensors and do complex math operations. The final output of the project is a small board containing the DSP and sensors, However I can notice that the evaluation board is quite large in size for my applications. So, here is my questions:-

1) What are the minimum required hardware on the board to make the DSP work with i2c/spi sensors, one GPIO interrupt, and few LEDs?

2) What is the need to the on-board FPGA in the evaluation board? will I need this FPGA to be implemented on my PCB to be able to control GPIO, sensors...etc?

I will be very grateful if you can answer my simple questions and help me choosing the correct HW.

  • 0
    TI__Mastermind 43660 points
    Ahmed,

    First of all i would like to know why did you select TMS320C6657 device for your application ?

    The C6657 device is an overkill for your design requirement. It is a multicore processor which is intended for military and communication systems. Please refer below link.

    www.ti.com/.../tms320c6657

    I would recommend you to chose C6748 which is low cost low power DSP and you could derive your design from C6748 LCDK.

    www.ti.com/.../tmdslcdk138

    Regards,
    Senthil
  • 0 in reply to Senthilkumar Srinivasan
    Intellectual 270 points
    Hi Senthil,

    Thank you for your response and help!
    Let me explain my issue please to let you better understand the HW selection. My project is to interface high accuracy inertial measurement unit with a controller which is supposed to be able to perform complex extended kalman filter calculations on the IMU output to get velocity and position data. The extended kalman filter loop is supposed to run @1000Hz. So, every 1ms the IMU sets an interrupt and sends the raw data over SPI/I2C, and the controller run the algorithm in less than 1ms to be able to catch the next interrupt and data correctly.
    My problem is that I have used TM4C123GH6PMI controller running at 80MHz with FPU enabled, the result was that the CPU takes 20ms to execute just one extended kalman filter loop while I need the time to be around 20x smaller than that! That's why I thought DSP would be great for my application. Also, I'm planning to put more advanced algorithms later in the code like real time kinematics with GPS for example, which will require processing power similar to the extended kalman filter requirements.
    In addition, my application needs at least one UART interface with the controller along with the i2c/spi.

    For such application, what is the best DSP available from TI please?

    Thank you,
    Ahmed
  • 0 in reply to ahmed helal59
    TI__Mastermind 43660 points
    Ahmed,

    I understand your requirement. The C6748 device that i suggested is having the maximum operating frequency of 456 MHz. I think your design requires the operating frequency more than this and higher processing power. To meet this, C665x would be a suitable option. If single core DSP is enough, you could opt for C6655.

    Answering your questions related to C665x based design.

    1. The minimum requirement to operate the device are power, clock, reset circuitry, external memory (as needed) and emulation circuitry (for debug purpose).

    2. The FPGA in TMDSEVM6657LS board is for power management and reset control. You may not need to have this FPGA in your board to control sensors.

    You could find below hardware design guide and schematics checklist helpful to develop your design.

    www.ti.com/.../sprabi2c.pdf

    processors.wiki.ti.com/.../Keystone_Multicore_Device_Family_Schematic_Checklist

    Regards,
    Senthil
  • 0 in reply to Senthilkumar Srinivasan
    Intellectual 270 points
    Hi Senthil,

    Thank you for your answers!

    I didn't find any special board for the CC6655 itself, However the current board we were talking about (TMS320C6657) is supposed to support the CC6655. So, I think i will use it.

    I still have some questions please, Is CCS available for free to use with the TMS320C6657 evaluation board? is there any limitation to CCS for use with either the TMS320C6657 or the CC6655 DSP please?
    Also, I didn't fully get the importance of FPGA on the board. I have read that it's connected to all the DSP GPIOs and that I must communicate with the FPGA to be able to control the GPIOs! is this true? and if it's true, how can I control the GPIOs and interrupts without an FPGA on my PCB design please?

    Looking forward to hear from you!

    Thank you,
    Ahmed
  • 0 in reply to ahmed helal59
    TI__Mastermind 28085 points

    Hi,

    I didn't find any special board for the CC6655 itself, However the current board we were talking about (TMS320C6657) is supposed to support the CC6655. So, I think i will use it.

    Yes, you can use C6657 EVM board for your testing. C6657 and C6655 DSP are same spec except DSP corepac. C6657  have two DSP core and C6655 have single DSP core.

    I still have some questions please, Is CCS available for free to use with the TMS320C6657 evaluation board? is there any limitation to CCS for use with either the TMS320C6657 or the CC6655 DSP please?

    CCS free version is enough for use the TMS320C6657 evaluation board with on-board XDS100 emulator. If you want to use High Speed Integrated  Mezzanine Emulator(XDS560v2 and XDS200) means you need to buy CCS license.

    Also, I didn't fully get the importance of FPGA on the board. I have read that it's connected to all the DSP GPIOs and that I must communicate with the FPGA to be able to control the GPIOs! is this true? and if it's true, how can I control the GPIOs and interrupts without an FPGA on my PCB design please?

    Yes, It is true. FPGA control the GPIO pins at DSP boot time only, after the DSP Boot user can use the GPIO pins for your application purpose.

    For more information refer EVM technical reference manual.

    Thanks,

  • 0 in reply to Ganapathi Dhandapani95
    Intellectual 270 points
    Hi Ganapathi,

    Thank you for your explanations and answers!

    one last question please, the i2c, spi, uart, and gpio signals are all 1.8v on the board, right? This means I will need a level converter to interface with 3.3v sensor for example and I will need at least one 1.8v pin from the board to the level converter to make it work. is there any available vcc pin on the board which is 1.8v ? also, is the board protected against connecting more than 1.8v for signals like i2c?

    Thank you,
    Ahmed
  • 0 in reply to ahmed helal59
    TI__Mastermind 43660 points
    Ahmed,

    Yes, you may need level converter to interface 1.8V level I2C, SPI signals to the 3.3V sensor. Please refer electrical specifications in the data manual for I2C operating voltage limits.

    Please refer C6657 EVM schematics in the below link for available 1.8V tapping point.

    www.einfochips.com/.../tms320c6657-evm.html

    Regards,
    Senthil