CrossLink Programming and Configuration Usage Guide
Technical Note
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FPGA-TN-02014-1.2
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Figure 5.1. Slave SPI Configuration Mode
The SSPI port is active when CrossLink is in Feature Row HW Default Mode state (that is, blank/erased). Diamond’s
default preference for the SLAVE_SPI_PORT is to ENABLE the port. Use the Spreadsheet View to ENABLE the SPI_PORT
preference in your design to keep the SSPI port active in User Mode.
The SSPI port is used to program and verify the NVCM or to configure the SRAM. The SSPI port can issue a REFRESH
command to make a newly programmed image active. Programming CrossLink using the SSPI port is complex. Lattice
provides ‘C’ source code called SSPIEmbedded to circumvent the complexity of programming CrossLink. Use
SSPIEmbedded to reprogram the CrossLink NVCM. To modify the SSPIEmbedded code as per the user-specific
environment programming master, refer to the
document.
5.5.
I
2
C Configuration Mode
CrossLink has an I
2
C Configuration port for use in accessing the Configuration Logic. An I
2
C master can communicate to
the Configuration Logic using 10-bit or 7-bit addressing modes. You can reprogram the NVCM or configure the SRAM
and access status/control registers within the Configuration Logic block. Note that only one of the SPI or I
2
C interfaces
can be operated at a time. When the I
2
C interface is activated, all subsequent communication to the SPI port is ignored,
even if in the middle of an active communication.
Table 5.5. I
2
C Port Pins
Pin Name
Description
SCL
I
2
C bus clock
SDA
I
2
C bus data line
The I
2
C Configuration port is available when CrossLink is in Feature Row HW Default Mode state (that is, blank/erased).
The default state set for the I2C_PORT in the Diamond design software is to place the I2C_PORT in the DISABLE state.
You must make sure the I2C_PORT is set to the ENABLE state to leave the I
2
C interface active in User Mode.
To enter Slave I
2
C mode, CRESETB pin should be held LOW while an external I
2
C Master writes the Activation Key (
) to the FPGA. During power up, the Activation Key must be written to CrossLink within 9.5 ms from V
CC
min while
CRESETB pin is held LOW.
