CrossLink Programming and Configuration Usage Guide
Technical Note
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. All other brand or product names are
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FPGA-TN-02014-1.2
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The MCCLK_FREQ has a range of possible frequencies available from 2 MHz up to 48 MHz (see the list on page 13). Do
not exceed the maximum clock rate of your SPI Flash, or of your printed circuit board.
Lattice recommends having a back-up configuration port available in case you specify a clock frequency that is out of
specification.
ENABLE_TRANSFR
The TransFR function used by CrossLink requires the configuration data loaded into the configuration SRAM and any
future configuration data file loaded into the external SPI Flash to have the ENABLE_TRANSFR set to the ENABLE state.
See the
Minimizing System Interruption During Configuration Using
for more information about using TransFR with CrossLink.
6.2.
Bitstream Generation Options
The Bitstream Generation options allow you to decide how the Diamond development tools create the configuration
data for the CrossLink device. The CONFIGURATION, USERCODE, and CUSTOM_IDCODE settings are saved in the
Feature Row and remain in effect until the Feature Row is erased. The other options allow you to control the BIT files
that are generated by Diamond.
CONFIGURATION
The BOOT_UP_SEQUENCE preference allows you to control the boot up sequence. The BOOT_UP_SEQUENCE
preference has five possible settings:
NVCM
— The NVCM setting is the SW default mode for building configuration data. The configuration bitstream is
stored in the Configuration NVCM.
NVCM-EXT
— This setting boots up the system using the NVCM first. If an error occurs, the system boots up with
the golden image in the External SPI Flash. This is the HW default mode for a blank device.
EXT-NVCM
— This setting boots up the system using the External SPI Flash first. If an error occurs, the system
boots up with the golden image in the NVCM.
EXT-EXT
— This setting enables the user to use the external SPI Flash itself to store two configuration images. This
setting boots up the system with the image kept at the first sector of the SPI Flash. If the system fails to boot with
the first image, the system boots up with the second golden image at the second sector.
EXTERNAL
— This preference generates configuration data that is stored in an external memory.
USERCODE
The CrossLink Configuration NVCM sector contains a 32-bit register for storing a user-defined value. The default value
stored in the register is 0x00000000. The USERCODE preference allows you to assign any value to a register. Suggested
uses include the configuration data version number, a manufacturing ID code, and date of assembly among others.
The format of the USERCODE field is controlled using the USERCODE_FORMAT preference. Data entry can be
performed in either Binary, Hex, or ASCII formats.
USERCODE_FORMAT
The USERCODE_FORMAT preference sets the format for the data field used to assign a value in the USERCODE
preference. The USERCODE_FORMAT has three options:
Binary
— USERCODE is set using 32 ‘1’ or ‘0’ characters.
Hex
— USERCODE is set using eight hexadecimal digits (that is 0-9A-F)
ASCII
— USERCODE is set using up to four ASCII characters
CDONE_PORT
CDONE and a GPIO are bonded to a shared package ball. This option enables the feature in the software.
If CDONE_PORT = CDONE_ONLY, the GPIO becomes unavailable to the user. If CDONE_PORT = CDONE_USER_IO, the
GPIO becomes available to the user.
