Which parameter decides on the size of a bit file?

[amitgangwar_vlsi]

hi...
Can anyone tell me that....on which parameter the size of a
bit file(which is downloaded onto the FPGA) depend?????

many many thanks in advance

amit gangwar

 

[echo47]

Size of bit file

If you are referring to a Xilinx FPGA, then the *.bit file size (in bytes) is approximately equal to one-eighth of the number of configuration bits for your FPGA type. For example, see "FPGA Configuration Bitstream Sizes" in the Xilinx "Spartan-3 Generation Configuration User Guide" UG332:
https://www.xilinx.com/support/documentation/user_guides/ug332.pdf

If you enable bitstream compression, then the file size may be smaller, but usually not much smaller.

 

[amitgangwar_vlsi]

Re: Size of bit file

thanks for replying....

according to the pdf size is fixed and depend upon the device...
is it right???

one more doubt i have....

if my design is occupying 30 % space on FPGA device....after doing some changes in the code ......if my code will occupy 60 % space on FPGA Device.... then what will happen... will bit file size be increased or not ????

plz make it more clear to me...

thanks a lot sir..

amit gangwar

 

[cherjier]

Size of bit file

"according to the pdf size is fixed and depend upon the device...
is it right??? "

yes, the file size is fix according to the FPGA device.

"if my design is occupying 30 % space on FPGA device....after doing some changes in the code ......if my code will occupy 60 % space on FPGA Device.... then what will happen... will bit file size be increased or not ???? "

no, the bit file size will still remain the same size.

 

[amitgangwar_vlsi]

Re: Size of bit file

thanks echo47 and cherjier for reply and for clarifying my doubt........

Amit Gangwar