PMU counter

Hello Arriy,

The event selection and other registers within the PMU are banked registers. To access them you must first select the the counter you are using via the PMNXSEL register (see section 6.3.6 in the Cortex-R4 and R4F r1p3 TRM you referenced.

i.e., if you write b00000 in the PMNXSEL register, you will be working with EVTSEL0 and PMC0. If you write b00001 to the PMNXSEL register, it will be EVTSEL1 and PMC1, and so on.

As a simple example, this is the init code generated by HalCoGen. Note the indexing of r0 to index to the different counter and selection registers.

;-------------------------------------------------------------------------------
; Initialize Pmu
; Note: It will reset all counters

    .def     _pmuInit_
    .asmfunc

_pmuInit_

        stmfd sp!, {r0}
        ; set control register
        mrc   p15, #0, r0, c9, c12, #0 
        orr   r0,  r0, #(1 << 4) + 6 + 1
        mcr   p15, #0, r0, c9, c12, #0
        ; clear flags
		mov   r0,  #0
		sub   r0,  r0,  #1
		mcr   p15, #0, r0, c9, c12, #3 
        ; select counter 0 event
        mcr   p15, #0, r0, c9, c12, #5 ; select counter
        mov   r0,  #0x11
        mcr   p15, #0, r0, c9, c13, #1 ; select event
        ; select counter 1 event
		mov   r0,  #1
        mcr   p15, #0, r0, c9, c12, #5 ; select counter
        mov   r0,  #0x11
        mcr   p15, #0, r0, c9, c13, #1 ; select event
        ; select counter 2 event
		mov   r0,  #2
        mcr   p15, #0, r0, c9, c12, #5 ; select counter
        mov   r0,  #0x11
        mcr   p15, #0, r0, c9, c13, #1 ; select event
        ldmfd sp!, {r0}
        bx    lr

    .endasmfunc

Arriy,

There are 3 pairs of registers here that we are concerned with. 3 EVTSEL registers and 3 PMC registers. Think of the PMNXSEL as a mux input that enables writing/reading each of the 3 pairs.  i.e., whenever you are configuring EVTSEL0 you have to first set PMNXSEL to b00000 first then write to the CP15_EVENT_SELECTION register. When you want to then configure EVTSEL1 you have to write PMNXWEL to b00001 first then write to CP15_EVENT_SELECTION register, etc. For clarity, i've created the following diagram that is a generic representation of how this works in regard to access to the register( teh diagram is not accurate with respect to the real hardware implementation and intended solely for explanation through a representative format).

So, as can be seen, the PMNXSEL simply controls/gates access to the registers for reading and writing. Once initialized the PMU will act on all three register sets. I believe there are provisions for configuring and enabling the PMU within Halcogen as well if you want example code on how it works.

Hello Chuck
Thanks to your advice is become easy understand.
I can understood register operation way.

I added figure what I would like to ask.

1. Use the PMNXSEL to set the events the EVTSEL0 and EVTSEL1 and EVTSEL2, respectively.
2.PMNXSEL is "b00010".This is Lastly set value.
3.At that time PMC 0, PMC 1, and PMC 2 are also counted?

Best Regards