Hi,
I am gonna ask a silly question here. How does the compiler recognize a data-structure as a register?
For example, in the header file ----" DSP2803x_EPwm.h" of the ePWM sample project from ControlSUITE
at the very bottom,it defines EPWM_REGS including all its member registers.
struct EPWM_REGS {
union TBCTL_REG TBCTL; // Time Base Control Register
union TBSTS_REG TBSTS; // Time Base Status Register
union TBPHS_HRPWM_GROUP TBPHS; // Union of TBPHS:TBPHSHR
Uint16 TBCTR; // Time Base Counter
........
}
//----------------------------------------------------------------------------------------
// External References & Function Declarations:
//
extern volatile struct EPWM_REGS EPwm1Regs;
extern volatile struct EPWM_REGS EPwm2Regs;
extern volatile struct EPWM_REGS EPwm3Regs;
I know the keyword ' extern' tells the compiler not to complain and ask the linker to find it, but how does it know, for instance, the member 'TBCTR' is a register variable?
Thanks,
Frank
