Hi, I am currently using an APEX20KE device.
When using the altclklock megafunction, I use OPERATION_MODE = NORMAL. I would like to know what is the function of the CLKLK_FB pin when in this mode? Does it act as a normal I/O? Thanks a lot!
- Paulo Valentim
I put this up on altera's site. They answered:
OK, when the ALTCLKLOCK is in Normal mode, CLKLK_FB inputs are not used by the PLL (i.e. the PLL ignores the external FB pin).
However, you cannot use the CLKFBIN pin (R6 for your device EP20K200EFI484-2X) as a general purpose I/O, as it is a dedicated input pin for use with the PLL only. (in the pinout file generated by Quartus this pins usage will be designated with a GND+ which means this pin should be connected to GND if unused.
Note however that pin P6 (CLKLK_FB2n) can be used as a general purpose I/o, as this is not a dedicated input pin.
Take care!!!
- Paulo Valentim
I put this up on altera's site. They answered:
OK, when the ALTCLKLOCK is in Normal mode, CLKLK_FB inputs are not used by the PLL (i.e. the PLL ignores the external FB pin).
However, you cannot use the CLKFBIN pin (R6 for your device EP20K200EFI484-2X) as a general purpose I/O, as it is a dedicated input pin for use with the PLL only. (in the pinout file generated by Quartus this pins usage will be designated with a GND+ which means this pin should be connected to GND if unused.
Note however that pin P6 (CLKLK_FB2n) can be used as a general purpose I/o, as this is not a dedicated input pin.
Take care!!!
- Paulo Valentim
I put this up on altera's site. They answered:
OK, when the ALTCLKLOCK is in Normal mode, CLKLK_FB inputs are not used by the PLL (i.e. the PLL ignores the external FB pin).
However, you cannot use the CLKFBIN pin (R6 for your device EP20K200EFI484-2X) as a general purpose I/O, as it is a dedicated input pin for use with the PLL only. (in the pinout file generated by Quartus this pins usage will be designated with a GND+ which means this pin should be connected to GND if unused.
Note however that pin P6 (CLKLK_FB2n) can be used as a general purpose I/o, as this is not a dedicated input pin.
Take care!!!
- Paulo Valentim
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