Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

Configuration flash size for Cyclone III

I'm designing a board with a Cyclone III on it and a microcontroller.

I need some guidelines on different ways of booting the Cyclone III and how big the flash needs to be. The Cyclone III comes in various sizes, how big of a flash would each model need for a full configuration?

I had previously considered storing the FPGA configuration on the microcontroller for ease of upgrades but I have a feeling I'm running out of flash on the microcontroller. I still need to implement a way of upgrading the FPGA config through the microcontroller using an ethernet loader.

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Bringing this thread back to life. Looking at that document and trying to estimate the configuration time. I intend to use an EP3C16 device in a n EQFP144 package and the image size is 4.1Mbit according to the document.

    However I'm not sure what kind of start-up time I can expect. The configuration time would be between 205ms and 103ms according to the manual but as far as I understand, that does not include the time it takes the device to power up (POR time). I'm a bit confused as to what exactly it means to switch between a standard or a fast POR time, what exactly I need to do in my circuit design to support a fast POR time, I understand there is a power requirement difference.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    In Stratix the POR duration depends on PORSEL pin.

    if LOW => 100msec

    if high => 12 msec

    same applies to the config device but:

    if LOW => 100msec

    if high => 2 msec

    It is recommended:

    12 msec for stratix, 100msec for config device to make sure who is ready first.

    As to power consumption difference, I am sure it is trivial.

    For config data size:

    You may consider the size of your largesst future device in case you decide to upgrade