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Altera_Forum's avatar
Altera_Forum
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15 years ago

Serial Flash Loader beside Differential IO

Hi Guys!

I am using an Cyclone III which has an AS-Device attached to it - on a nearby pin an LVDS signal is generated. To program the configuration device, I would like to use Altera's Serial Flash Loader. Unfortuantely the fitter cannot complete it's operation sucessfully, cancelling with the following message: 

Error: Pad 15 of non-differential I/O pin 'SFL:SFL1|altserial_flash_loader:altserial_flash_loader_component|\GEN_ASMI_TYPE_1:asmi_inst~ALTERA_DCLK' in pin location 12 is too close to pad 13 of differential I/O pin 'framesync_out' in pin location 10  --  pads must be separated by a minimum of 5 pads. Use the Pad View of Pin Planner to debug.
Error: Pad 15 of non-differential I/O pin 'SFL:SFL1|altserial_flash_loader:altserial_flash_loader_component|\GEN_ASMI_TYPE_1:asmi_inst~ALTERA_DCLK' in pin location 12 is too close to pad 14 of differential I/O pin 'framesync_out_bar' in pin location 11  --  pads must be separated by a minimum of 5 pads. Use the Pad View of Pin Planner to debug.
Since the EPROM is only accessed while configuration, the LVDS signal isn't active at all, so there cannot be any interference. Therefore the error must be obsolete. I found in AN466 the toggling rate of the nearby (configuration)pins of the LVDS signal has to be set to 0MHz. However, I cannot find them in the assingment editor, they must be sort of hidden.

Do you know a way how I could use the SFL in my design anyway?

Many thanks for any reply!

3 Replies

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

    ~ALTERA_DCLK~ would be the pin name. Pretty sure that should be enough to get you to the 0MHz setting. If not, configure it as a regular io pin and then drive it to ground(or VCC, don't know which is best), then hit the 0MHz setting to that pin name.

    Hope this helps.

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

    I tried to implement the maximum toggle frequencies as suggested by kbs982's posting, but it didn't work.

    However, by incidence I found at the SFL-instance the following pins:

    SFL:inst|altserial_flash_loader:altserial_flash_loader_component|\GEN_ASMI_TYPE_1:asmi_inst~ALTERA_DCLK

    SFL:inst|altserial_flash_loader:altserial_flash_loader_component|\GEN_ASMI_TYPE_1:asmi_inst~ALTERA_SCE

    SFL:inst|altserial_flash_loader:altserial_flash_loader_component|\GEN_ASMI_TYPE_1:asmi_inst~ALTERA_SDO

    SFL:inst|altserial_flash_loader:altserial_flash_loader_component|\GEN_ASMI_TYPE_1:asmi_inst~ALTERA_DATA0

    When I entered them in the Assignment Editor, everything was working fine.

    Thanks for your help anyway!