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LAUNCHXL-F28377S: Speed of communication moduls

Stefan Maier25
Prodigy 110 points

Part Number: LAUNCHXL-F28377S

Hi everybody,

I have a question about the Moduls of communication. I want to try a fast communication between Master and 1 or 2 Slaves. So I searched in datasheet how fast each communication-Modul is. Because i couldn´t find a answer, i would ask the TI community.

How fast are the following communications:

SPI

SCI

McBSP

uPP

...

Since yet, I tried SPI and McBSP. But in SPI i only could do a 20 MHz Baudrate. In Datasheet stays "max. 50MHz in High Speed Mode". But i couldn´t reach this value, althought i set HS_MODE to 1.

McBSP had problems with higher Baudrates than 3,125 MHz. (SYSCLK (200 MHz) / LSPCLKDIV (4) and /CLKGDV (16) = 3,125MHz)

For this tests I connected a Master F28377s Launchpad with a Slave F28377s Launchpad.

I hope someone can write something about "Where I find the max. speed" and maybe about "how much Baudrate is OK for communication and which isn´t good or impossible".

Thanks!

Best wishes

Stefan

  • 0
    TI__Guru* 95315 points
    Stefan,
    The communication modules you describe differ widely in terms of features and their abilities (think synchronous Vs asynchronous, serial Vs parallel, word-size, point-to-point Vs multiple-devices on a bus etc). Technically, all protocols transfer "data", but one protocol is more suitable than others and some protocols are just not usable for the task at hand. So, the answer to your question depends completely on what you want to do. Since you say "Master and 1 or 2 slaves", CAN or I2C may be more suitable. Technically, you could use SCI (with RS-485), but from a hardware perspective, CAN or I2C would be simpler. You also need to take into account the distance between nodes. If the nodes are on the same board, I2C is good. If they are much farther apart, CAN may be better. You cannot choose the module solely based on speed-of-communication.
  • 0 in reply to Hareesh Janakiraman
    Prodigy 110 points
    Hi Hareesh,
    thank you for your answer. I thought I can choose a communication with my points "speed" "distance" and "multi-devices".

    Why I search a communication with high-speed? Here´s the background:
    I want 2 Slaves which each of them control a power inverter for a motor for example. The slaves should be measure the current and do the PWM for the power inverter. The Master have to ask the slaves for the measurement values (I calculate with 2 values with 16 bit) and because of the measurment the master have to calculate and send the slaves the new PWM duty cycle.
    I know that FPGA is faster than a microcontroller. But I want to see what my microcontroller can reach in the topic "speed" from communications.
    That´s why I search a fast communication with 2x16Bit values from Master to Slave and Slave to Master. The Distance is a short distance. Master is close to the Slaves.
    At the moment I read the documentation about the parallel Modul uPP. That will be my next test.

    I hoped with this thread, that someone can say which communication has a higher Bit/s (Baudrate) or transmission speed, or where I can read something about it.

    Best wishes
    Stefan
  • 0 in reply to Stefan Maier25
    TI__Guru* 95315 points
    You may want to look at SPI modules.