S12ZVL assembler loading 32 bit value to D6,D7

[guide19]

Hi,

I am writing loader in assembler for S12ZVL device. I am trying to load 32bit registers D6 and D7 with address stored in RAM but without succes. Could you please help me?

definition of the comm. port:

ComPort   equ PTT

Here is how my variables are defined:

; variable/data section

MY_EXTENDED_RAM: SECTION

; Insert here your data definition.

StartAddr        ds.l 1

EndAddr          ds.l 1

ActualPageAddr   ds.b 1

WhichArea        ds.b 1

the variables are filled wit this procedure: hdsk is step, where the data are set to port T from the master.

  BSR hdsk

  MOV.B ComPort,StartAddr+1

  BSR hdsk

  MOV.B ComPort,StartAddr+2

  BSR hdsk

  MOV.B ComPort,StartAddr+3

  BSR hdsk

  MOV.B ComPort,EndAddr+1

  BSR hdsk

  MOV.B ComPort,EndAddr+2

  BSR hdsk

  MOV.B ComPort,EndAddr+3

and the next step I would like to do is to load 32 bit value StartAddr to D7 register.

I try:

LD D7,StartAddr

but when I do it this way, only one byte is loaded to D7... bits 0-7 of the D7 with value on StartAddr.

How to load whole 32 bit value stored in StarAddr variable?

[RadekS]

Hi Jozef,

I tested your code on our board and everything works fine on my side.

ComPort  equ PTT
; variable/data section
MY_EXTENDED_RAM: SECTION
StartAddr  ds.l 1
EndAddr    ds.l 1
EndlessLoop:
            LD D6, #$01234567    ;Start
            ST D6, StartAddr    ;Start
            LD D6, #$76543210    ;End
            ST D6, EndAddr    ;end
; now StartAddr contains 0x01234567 and EndAddr contains 0x76543210
            MOV.B ComPort,StartAddr+1
            MOV.B ComPort,StartAddr+2
            MOV.B ComPort,StartAddr+3
            MOV.B ComPort,EndAddr+1
            MOV.B ComPort,EndAddr+2
            MOV.B ComPort,EndAddr+3
; since PTT has stable 0x00 value, it rewrites lowest 3 bytes from StartAddr and EndAddr addresses.
; now StartAddr contains 0x01000000 and EndAddr contains 0x76000000
            LD D7,StartAddr    ;Load Start
; now D7 contains 0x01000000
; when I comment out MOV.B instructions, D7 will contains 0x01234567

Could you please check whether described behavior is expected for your application?

Please check whether port T is in input mode (DDRTx=0).

Please check whether some of the pins are not affected by any externally connected circuit or whether they are not dedicated to any other function like timer (if you use output compare channels, please disconnect timer from pins by OCPD register)

The opcode for LD D7,StartAddr command is 0xB7001104 (StartAddr starts at address 0x1104).

Could you please check opcode on your side?

I hope it helps you.

Have a great day,
Radek

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[guide19]

I have tried your code and it is working correct. Thanks for the support.