Tutorial: Creating a Custom Bitfile
This page covers the creation and installation of a custom personality/bitfile (a modification of the vector adder sample project).
Building a Bitfile
Copy the newest version of the example project and set your environment variables if you have not done so already. You can make a small modification to the verilog code if you wish, such as making it a vector subtractor instead of a vector adder.
Next, compile your bitfile:
cd ~/pdk_sample/cae_vadd/phys make
The bitfile will take a long time to create (while the Reference Manual states 2 to 4 hours, it may take much longer). Be patient.
Next, package your bitfile using the command:
make release
FPGA Usage Statistics
The device usage statistics are displayed on the terminal while building the bitfile. The log is saved to disk at:
{project directory}/phys/cae_fpga.map
Search the end of the log file for "Design Summay" for a percentage break down in LUT, Flip flop, and BRAM usage.
Choose a New Signature
Custom personalities should not use the default PDK signature (4.1.1.1.0). Choose a new signature between 65000 and 65535. In this example, we will use 65123.1.1.1.0.
You will need to create a new directory and copy the pertinent files to this directory:
cd /opt/convey/personalities mkdir 65123.1.1.1.0 cd 65123.1.1.1.0 cp /home/PROJECT_RELEASE/DATE/cae_fpga.tgz ./ae_fpga.tgz
This is the only required file, but you may copy PersDesc.dat from the default PDK folder to your new folder and uncomment additional custom instructions you have used.
cp /opt/convey/personalities/4.1.1.1.0/PersDesc.dat ./
Instead of adding a new directory to Convey's personality folder as done above, you may set the CNY_PERSONALITY_PATH environment variable to any directory, i.e.
export CNY_PERSONALITY_PATH=/home/PROJECT_PATH/ or setenv CNY_PERSONALITY_PATH /home/PROJECT_PATH/
The default when the CNY_PERSONALITY_PATH is not set is to use the /opt/convey/personalities folder.
You will also need to update the customdb file in /opt/convey/personalities (or create your own customdb file in your user defined personalities folder). This file is used by the cny_get_signature function and converts strings to a signature number. Our customdb file contains the following text:
65123.1.1.1.0,subtractor
Finally, there are certain places in the code where you should ensure that the signature has been updated.
- In the simulator (/sim/CaeIsaVadd.cpp), update: #define PERS_SIGN_CAE 0xfe63001000101000LL, where 0xfe63 is the hex value for your signature (65123).
- In the C code, (SampleAppVadd/UserApp.c) update: cny_get_signature("subtractor", &sig, &sig2, &stat);, where "subtractor" is the pseudo name of your CAE given in the customdb file.
- In the assembly code, (SampleAppVadd/cpVadd.s) update the signature directive: .signature pdk=65123
When you change the personalities directory, flush the MP cache. This will unload the current bitfile:
/opt/convey/sbin/mpcache -f
You can also add a signature, and preload a given bitfile by using the commands:
/opt/convey/sbin/mpcache -add -S<personality> /opt/convey/sbin/mpcache -load -S<personality>
Additional details are available in Appendix D of the Convey PDK Reference Manual (.pdf).
See Also
References
- Convey PDK Reference Manual (.pdf) - Sections 9.4.6, 9.4.7, 10, Appendix D