Lattice Semiconductor CrossLink - 3 Definition of Terms

CrossLink Programming and Configuration Usage Guide
Technical Note
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6 FPGA-TN-02014-1.2
3. Definition of Terms
This document uses the following terms to describe common functions:
 BIT – The BIT file is the configuration data for CrossLink that is stored in an external SPI Flash. It is a binary file and
is programmed unmodified into the SPI Flash.
 Configuration – Configuration refers to a change in the state of the CrossLink SRAM memory cells.
 Configuration Data – This is the data read from the non-volatile memory and loaded into the FPGA’s SRAM
configuration memory. This is also referred to as a bitstream, or device bitstream.
 Configuration Mode – The configuration mode defines the method CrossLink uses to acquire the configuration
data from the non-volatile memory.
 Dummy Byte – A dummy byte is any data in which the numeric value is considered to be invalid. In some cases,
external devices controlling the resident FPGA scan in dummy bytes as a requirement of the protocol.
 Internal NVCM – The BIT file can be programmed directly into the internal NVCM. The user does not need to know
where an actual page of the configuration data starts. The CrossLink configuration engine handles the parsing in
the NVCM to SRAM transfer.
 Number Formats – The following nomenclature is used to denote the radix of numbers
 0x: Numbers preceded by ‘0x’ are hexadecimal
 b (suffix): Numbers suffixed with ‘b’ are binary
 All other numbers are decimal
 NVCM – Internal, lowest-cost, secure, one-time programmable Nonvolatile Configuration Memory.
 Port – A port refers to the physical connection used to perform programming and some configuration operations.
Ports on CrossLink include SPI and I
2
C physical connections.
 Programming – Programming refers to the process used to alter the contents of the internal or external
non-volatile configuration memory.
 User Mode – CrossLink is in User Mode when configuration is complete, and the FPGA is performing the logic
functions it was programmed to perform.