Hi expert, 

I met this issue today on my CCS project with SYSBIOS, I use the latest SYSBIOS (bios_6_83_00_18)，and I edit a cmd file (TMS320F280039C.cmd) according to TMS320F280039C，because there is no corresponding cmd file in bios_6_83_00_18,  I can't recover to the state will error not happens. Console contents read below:

"C:\\ti\\ccs1120\\ccs\\utils\\bin\\gmake" -k -j 8 all -O

Building file: "../app.cfg"
Invoking: XDCtools
"C:/ti/ccs1120/xdctools_3_62_01_16_core/xs" --xdcpath="C:/ti/ccs1120/ccs/bios_6_52_00_12/packages;" xdc.tools.configuro -o configPkg -t ti.targets.elf.C28_float -p ti.platforms.tms320x28:TMS320F280039C -r release -c "C:/ti/ccs1120/ccs/tools/compiler/ti-cgt-c2000_21.6.0.LTS" --compileOptions "-g" "../app.cfg"
making package.mak (because of package.bld) ...
generating interfaces for package configPkg (because package/package.xdc.inc is older than package.xdc) ...
configuring app.xe28FP from package/cfg/app_pe28FP.cfg ...
subdir_rules.mk:12: recipe for target 'build-652693487-inproc' failed
error: ti.sysbios.BIOS: "C:/ti/ccs1120/ccs/bios_6_52_00_12/packages/ti/sysbios/BIOS.xs", line 248: ti.sysbios.BIOS cpuFreq.lo: BIOS.cpuFreq is undefined. You must define the CPU frequency in your application configuration. For example, if the PLL is being configured for 100MHz, add this to your application configuration script: BIOS.cpuFreq.lo = 100000000;
js: "C:/ti/ccs1120/xdctools_3_62_01_16_core/packages/xdc/cfg/Main.xs", line 160: Error: Configuration failed!
gmake.exe: *** [package.mak:204: package/cfg/app_pe28FP.xdl] Error 1
js: "C:/ti/ccs1120/xdctools_3_62_01_16_core/packages/xdc/tools/Cmdr.xs", line 52: Error: xdc.tools.configuro: configuration failed due to earlier errors (status = 2); 'linker.cmd' deleted.
gmake[1]: *** [build-652693487-inproc] Error 1
gmake: *** No rule to make target 'build-652693487', needed by 'configPkg/compiler.opt'.
gmake: *** No rule to make target 'build-652693487', needed by 'configPkg/linker.cmd'.
gmake: Target 'all' not remade because of errors.

**** Build Finished ****

Could you let me know the root casue can help me solve this?

note:I use the same way to buid SYSBIOS project successfully using TMS320F280049C.

Thanks