Warning: Current chip does not have enough common (non-banked) RAM with pic 16f526

[Orlando D.]

I have a problem using pic 16f526, i get an insufficient memory ram warning message but if i cut "readad (an0)" it does not happen .
What can i do to use ad conversion with this pic ?

Thank in advance
Orlando

Chip 16f526

 #option explicit
     #config Osc = IOSCFS_4MHZ

; ----- Define Hardware settings
' Dir SerInPort In
DIR portb in ' setta porta in ingresso per evitare cortocircuiti
DIR portb.0 in ' ADC0
DIR portb.1 in ' TASTO +
DIR portb.2 in ' TASTO -
DIR portb.4 out
DIR portb.5 out 'relais

DIR portc in' setta porta in ingresso per evitare cortocircuiti
DIR portc.0 Out
DIR portc.1 Out
DIR portc.2 Out
DIR portc.3 Out
DIR portc.4 Out

; ----- Constants

; ----- Variables
DIM adval as byte 'variabile per ADC0

Do
adval = Readad(AN0)
adval =adval + 1
loop
End

[Anobium]

Hello,

Warning: Current chip does not have enough common (non-banked) RAM. This is warning and the code may operate as required however to resolve change the use of the wait or time related instructions to remove warning message.

The NoBankRAM section in the chip data file refers to the area of microprocessor RAM that can be accessed regardless of which bank is currently selected.

Example, the 16F59 does have RAM from 0x0A to 0x1F in bank 0, but only 0x0A to 0x0F can be accessed while another bank is selected. If for example bank 3 is selected, the PIC would be working with addresses between 0x60 and 0x7F. Accessing 0x6A to 0x6F would map back to 0x0A to 0x0F, but accessing 0x70 would access location 0x70 (not 0x10).

This is NOT caused by the ADC code. The code for this chip, when optimised, is as below - which is not to shabby.

;Overloaded signature: BYTE:
FN_READAD2
;***************************************
;Perform conversion
;LLReadAD 1
;SET ANS0 OFF
    bcf ADCON0,ANS0
;SET ANS1 OFF
    bcf ADCON0,ANS1
;SET ADCS1 OFF
    bcf ADCON0,ADCS1
;SET ADCS0 ON
    bsf ADCON0,ADCS0
;SET CHS0 OFF
    bcf ADCON0,CHS0
;SET CHS1 OFF
    bcf ADCON0,CHS1
;IF ADReadPort.0 On Then Set CHS0 On
    btfsc   ADREADPORT,0
    bsf ADCON0,CHS0
;IF ADReadPort.1 On Then Set CHS1 On
    btfsc   ADREADPORT,1
    bsf ADCON0,CHS1
;SET ADON ON
    bsf ADCON0,ADON
;Wait AD_Delay
    movlw   2
    movwf   SysWaitTemp10US
    call    Delay_10US
;SET GO_NOT_DONE ON
    bsf ADCON0,GO_NOT_DONE
;nop
    nop
;Wait While GO_NOT_DONE ON
SysWaitLoop1
    btfsc   ADCON0,GO_NOT_DONE
    goto    SysWaitLoop1
;SET ADCON0.ADON OFF
    bcf ADCON0,ADON
;SET ANS0 OFF
    bcf ADCON0,ANS0
;SET ANS1 OFF
    bcf ADCON0,ANS1

;ReadAD = ADRES
    movf    ADRES,W
    movwf   READAD
    retlw   0

[Anobium]

A method to create a HEX is to take the ASM from Great Cow BASIC and rip the code apart to remove the WAIT. I have taken the ASM above and taken to its essence removing the wait.

This was not AD wait, you could try NOPs

'
#Chip 16f526
     #option explicit
         #config Osc = IOSCFS_4MHZ
; ----- Define Hardware settings
 ' Dir SerInPort In
'  DIR portb in ' setta porta in ingresso per evitare cortocircuiti
  DIR portb.0 in ' ADC0
  DIR portb.1 in ' TASTO +
  DIR portb.2 in ' TASTO -
  DIR portb.4 out
  DIR portb.5 out 'relais

'  DIR portc in' setta porta in ingresso per evitare cortocircuiti
  DIR portc.0 Out
  DIR portc.1 Out
  DIR portc.2 Out
  DIR portc.3 Out
  DIR portc.4 Out

; ----- Constants

; ----- Variables
  DIM adval as byte 'variabile per ADC0

   Do
         adval = myReadAD

         adval =adval + 1
    loop
   End


function myReadAD

      ADCON0 = 0b00100000

      'Removed....
      'Wait AD_Delay

      SET GO_NOT_DONE ON
      ASM nop
      Wait While GO_NOT_DONE ON
      SET ADCON0.ADON OFF
      myREADAD = ADRES

end Function

Anyone else got idea how to resolve? We have a number of chips with this banked issue.

[kent_twt4]

Baseline 10f, 12f, 16f chips will always be difficult to manage. Using assembly is required if something more than a blinky led or basic port pin switching.

Here is a "rough" routine to call for delay periods that could help. Put on a dvm or scope to figure out more precise delays.

sub Delay1s (fraction255) 'i.e. 255 equals 1 sec

'Option_Reg = b'11000011' 'prescale is 16
  clrf TMR0
  For Delay = 1 to fraction255  '0.998337 s
    For Delay2 = 1 to 29  '0.003915 s
      Delay3:   '129us delay
      btfss TMR0,7
      goto Delay3
      clrf TMR0
    Next
  Next

end sub

I remember that a very compact cycle accurate delay was made in assembly that was on Piclist or ElectrotechOnline forum. Some people have a mission to complete in least amount of program words possible.

[Orlando D.]

Thanks for your attention and prompt reply , i will try later in this days

[Orlando D.]

I have find this solution for ad problem on pic 16f526
searching on pic data sheet.

DIM adval as byte 'variable per ADC0
movlw 69 "hex set AN#2 "01101001"
movwf adcon0
bsf adcon0, 1 "start conversione a/d #2
loop0:
btfsc adcon0, 1 "if bit1 =0 = end convers a/d else loop0
Goto loop0
movf adres, w "Read value in adres
movwf adval "Save result in adval"
'end conversion a/d

No wait instructions because this routine wait end conversion
bit adcon,1

[William Roth]

Here is the same code using BASIC instead of inline ASM:

 #chip 16f526,8
 DIM ADVAL as Byte
ADCON0 = 0b01101001
SET ADCON0.1 ON
Wait until ADCON0.1 = 0
ADVAL = adres

End