Here is the test program...

Code:
'************************************************************************
'   Programme: Shiftout Test PBP   (c)Roger LEGAT 07-2023
'   RX Tester---> PIC 12F675
' PicBasicPro Compiler V:2.40   ---> 393 Words used
'************************************************************************
'*** PIC Pinouts/Specifications
'------------------------------------
'            PIC 12F675
'                   __ __
'           Vcc +|  U  |- Gnd
'        GPIO.5 x|     |< GPIO.0
'        GPIO.4 >|     |> GPIO.1 _DIO
'        GPIO.3 >|     |> GPIO.2 _CLK
'                    -----

@ Device Pic12F675, intrc_osc, wdt_off, pwrt_on, mclr_off, protect_off

DEFINE OSC 4    ' Pulsin/Pulsout Resolution    =10µsec    => 1ms=100
'   (Pulse Value of 1msec x10 =1000)    [x10]
'  Pause =1msec => 1msec=1    1sec=1000

Include "modedefs.bas"   ;for shiftout command

CMCON  = 7   'Comparator Off
ANSEL  = 0   'Set Port to Digital i/o         
ADCON0 = 0   'All ADC Off
 
Asm
 bsf STATUS      ;Bank 1
 call 3FFh       ;Get the CAL value from 3FF addresse YOU WRITE BEFORE !
 movwf OSCCAL    ;Calibrate
 bcf STATUS, RP0 ;Bank 0
Endasm

'*** In/Out pins ..................................................
 Output 1 : _DIO var GPIO.1
 Output 2 : _CLK var GPIO.2

'*** Variables/Constants
  Pack       VAR BYTE        ;Byte to send
  
 '=== MAIN PROGRAM =====================================================

 Pack = 255

MainLoop:
 
   Shiftout _DIO,_CLK,LSBFIRST,[Pack\8] 'Send Byte
   pause 100

Goto MainLoop


;=========== END OF PBP =================================================