• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 98 subscribers
  • Views 595 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Minimal configurations AM3352

Albin Marchewka
Prodigy 130 points
Other Parts Discussed in Thread: AM3352

Hi, 

I'm willing to use the AM3352 chip in order to have a switch ethernet and  a modbus server.
Also I won't install a Linux on it. I had a look and it seems unclear for me whether or not we need to have external RAM and Flash.
I know the chip already have some, but in every build systems I have seen, they add external ram and flash, would it be enough, as i'm not gonna use a Linux on the chip,  to keep it this way ? 
What is the minimal configurations ?

Thanks.

  • 0
    TI__Guru*** 125430 points
    You definitely need external flash. There is not any non-volatile memory in the AM335x, so you need external flash to boot (unless you're planning to use one of the peripheral boot modes like UART or Ethernet).

    There's not a lot of internal SRAM, so in my opinion you need to have external DRAM. It would be a substantial engineering effort trying to get everything to fit internally. At a minimum, you would likely want to have DRAM for the initial development so you have a little space for debugging or other features. It's doubtful you could make it completely fit into internal SRAM. Unless you have extremely high volumes, this does not seem like a good investment of effort. In my opinion you would be better off buying the DRAM and getting your product out the door more quickly!
  • 0 in reply to Brad Griffis
    Prodigy 130 points

    We've chosen this chip because of the emebeded ethernet switch, and the possibility to use ethercat, also we want to implement a motor control loop. We were thinking to use TI-RTOS. The question of using or not DRAM is considerating because my pcb needs to be very small, we have a defined constraint on it and thats mean we don't have place for unnecessary components.

    As you can see we don't really need all the features offred by this chip neither all the perf available. The chip has got 176K of ROM and  64K of RAM. We agree it's not much, but we've been working for a while on different microcontrollers and we didn't need much RAM. That's why we're wondering if we have a really need of an external DRAM. According to you, would it be really dificult to make a such apllication fit in internal SRAM ?

  • 0 in reply to Albin Marchewka
    TI__Guru*** 125430 points

    Albin Marchewka said:
    The chip has got 176K of ROM and  64K of RAM.

    Not quite.  Here's a screenshot I marked up from the TRM's memory map:

    The "Boot ROM" area is code written by TI to load user code into RAM.  So in particular, the "normal" way of using this device is that both code and data reside in RAM.  In terms of RAM there is a total of 127 KB.  The "SRAM internal" is accessible only by the ARM, i.e. it is "internal" to the ARM.  The L3 OCMC0 is accessible to the whole chip (e.g. DMA, USB, Ethernet, etc.).

    Now there are some additional "tricks" you could play.  For example, if you use parallel NOR flash as your boot device, you can actually execute code directly from parallel NOR flash.  That could enable you to execute all your code directly from NOR and use all the RAM for data.  So there are tricks like this that you can play.  However, I still think it would be a lot of engineering effort to get your data usage down to 127 KB of RAM. 

  • 0 in reply to Brad Griffis
    Prodigy 130 points
    Thank you for the clarification, I understand now why it may be effortless to add external RAM.

    It is time to learn DDR routing :)