Handling a lot of text data, any simple and practical ways?

[CuriousOne]

Thanks!
I had a almost similar approach -
The text is stored in EEPROM part of the IC, in series.
There is a 40 byte area at beginning in EEPROM, which
has offset and length entries for these text messages
so all I have to do, to say display "Set Time" is call a routine like

READ 1,A 'read offset
READ 2,B 'read length
FOR C=A to A+B 'define a loop from this to that
READ C,D 'read eeprom at needed value
LCDOUT $FE,D,$14 'Display char and move cursor to next char
NEXT

But for some reasons it does not works, seems like that LCDOUT on initialization, resets the offset set by $14 (move cursor right)

[HenrikOlsson]

LCDOUT $FE,D,$14 'Display char and move cursor to next char

That line of code does NOT do what the comment says.

You're telling it to interpret whatever you read from EEPROM (into the D variable) as a command, then you're sending a constant $14 which it will interpret as data and print whatever character that code corresponds to (see datasheet).

To do what the comment says it would look like this:

LCDOUT D, $FE, $14

With that said, the adress counter in the HD44780 will automatically increment each time you write to DDRAM (ie send it a byte not preceded by $FE) so by doing the above you will end up with a blank space between the characters.

[CuriousOne]

Oh thanks, will give it a try!

[richard]

on a 16f like this

;16f1825#CONFIG
             __config        _CONFIG1,    _FOSC_INTOSC & _CP_OFF & _WDTE_OFF &  _PWRTE_ON  &  _MCLRE_ON  & _CLKOUTEN_OFF
              __config      _CONFIG2, _PLLEN_ON & _LVP_OFF
#ENDCONFIG


DEFINE OSC 32    
    OSCCON=$70
    ANSELA=0
    ANSELC=0
    TRISA = %001110
    trisc = %11100010     ' set PORTC I/O
    Strings CON EXT


    i VAR BYTE
    Char VAR BYTE
    ctemp  VAR WORD
    StringNumber VAR BYTE
    StartAddress VAR WORD
    rand      VAR WORD
    lata.0=1 
    DEFINE DEBUG_REG PORTA
    DEFINE DEBUG_BIT 0      ;  if not used for pwr  
    DEFINE DEBUG_BAUD 9600
    DEFINE DEBUG_MODE 0     
    pause 2000
    Debug "Start",13 ,10  
Goto OverStrings
ASM
Strings
    ; Strings, fixed length, 20 characters including null terminator.
    ; Actual string terminatesends with a NULL and is then padded to exactly 20 chars.
    da "Set Year", 0, "           "    ; 0
    da "Set Month", 0, "          "    ; 1
    da "Set Date", 0, "           "    ; 2
    da "Set day of week", 0, "    "    ; 3
    da "Set Hour", 0, "           "    ; 4
    da "Set Minute", 0, "         "    ; 5 
    da "Set alarm mode", 0, "     "    ; 6
    da "Off", 0, "                "    ; 7
    da "On all week", 0, "        "    ; 8
    da "On without weekends", 0, ""    ; 9
    da "Set alarm hours", 0, "    "    ; 10
    da "Set alarm minutes", 0, "  "    ; 11
    da "Set display format", 0, " "    ; 12
    da "Imperial (12Hr/F)", 0, "  "    ; 13
    da "Metric (24Hr/C)", 0, "    "    ; 14
    da "Display brightness", 0, " "    ; 15
    da "Auto", 0, "               "    ; 16
    da "25%", 0, "                "    ; 17
    da "50%", 0, "                "    ; 18
    da "75%", 0, "                "    ; 19
    da "100%", 0, "               "    ; 20
ENDASM
OverStrings: 


Start:
    Debug "Program start",13,10 
    Debug "Address of first string: $", HEX4 Strings, 13 ,10


Action:    
     RANDOM  rand 
    StringNumber = rand//20                               ' Select which string to print
    GOSUB PrintString                               ' And, you guessed it, go print it.
     PAUSE 1000
    goto  Action
END


PrintString:   
    StartAddress = Strings + (StringNumber * 11)    ' Precalculate address of first char of string in question
    For i = 0 to 19                                 ' Maximum string length is 20 characters
        ReadCode (StartAddress + i), CTEMP           ' Get a char from string in question.
      Char = (CTEMP>>7) 
        IF (Char = 0) THEN EXIT                     ' Break out if char is NULL
        Debug Char                                   ' Otherwise print it
     Char = CTEMP&$7f        
       IF (Char = 0) THEN EXIT                     ' Break out if char is NULL
        Debug Char                                ' Otherwise print it
    NEXT
RETURN

or if all that padding is troubling , using random length null terminated strings

;16f1825#CONFIG
             __config        _CONFIG1,    _FOSC_INTOSC & _CP_OFF & _WDTE_OFF &  _PWRTE_ON  &  _MCLRE_ON  & _CLKOUTEN_OFF
              __config      _CONFIG2, _PLLEN_ON & _LVP_OFF
#ENDCONFIG


DEFINE OSC 32
    OSCCON=$70
    ANSELA=0
    ANSELC=0
    TRISA = %001110
    trisc = %11100010     ' set PORTC I/O
    Strings CON EXT
    i VAR BYTE
    Char VAR BYTE
    ctemp  VAR WORD
    rand   VAR WORD
    StringNumber VAR BYTE
    StartAddress VAR WORD
    isa   VAR WORD
    lata.0=1 
    DEFINE DEBUG_REG PORTA
    DEFINE DEBUG_BIT 0      ;  if not used for pwr  
    DEFINE DEBUG_BAUD 9600
    DEFINE DEBUG_MODE 0     
    pause 2000
    Debug "Start",13 ,10  
Goto OverStrings
ASM
Strings
    ;  string terminates with a NULL 
    da "Set Year", 0     ; 0
    da "Set Month", 0     ; 1
    da "Set Date", 0    ; 2
    da "Set day of week", 0    ; 3
    da "Set Hour", 0     ; 4
    da "Set Minute", 0     ; 5 
    da "Set alarm mode", 0     ; 6
    da "Off", 0    ; 7
    da "On all week", 0     ; 8
    da "On without weekends", 0   ; 9
    da "Set alarm hours", 0    ; 10
    da "Set alarm minutes", 0     ; 11
    da "Set display format", 0    ; 12
    da "Imperial (12Hr/F)", 0    ; 13
    da "Metric (24Hr/C)", 0    ; 14
    da "Display brightness", 0    ; 15
    da "Auto", 0    ; 16
    da "25%", 0     ; 17
    da "50%", 0    ; 18
    da "75%", 0     ; 19
    da "100%", 0     ; 20
    dw 3            ;eof
ENDASM
OverStrings:


Start:
    Debug "Program start",13,10 
    Debug "Address of first string: $", HEX4 Strings, 13 ,10


Action: 
    RANDOM  rand 
    StringNumber = rand//20                             ' Select which string to print
    GOSUB findIndex  
    GOSUB PrintString                               ' And, you guessed it, go print it.
    PAUSE 1000
    goto  Action
END


findIndex:
    isa    = Strings
    while StringNumber
        ReadCode isa, CTEMP
        isa=isa+1
        if  CTEMP ==3 then 
            isa=0
            return
        endif
        if (CTEMP.highbyte==0) then  
            StringNumber=StringNumber-1
            if    StringNumber == 0 then  return
        endif
    wend
return 


PrintString: 
    if  isa then
        Debug 13,10
        For i = 0 to 19                                 ' Maximum string length is 20 characters
            ReadCode (isa + i), CTEMP           ' Get a char from string in question.
            Char = (CTEMP>>7) 
            IF (Char = 0) THEN EXIT                     ' Break out if char is NULL
            Debug Char                                   ' Otherwise print it
            Char = CTEMP&$7f        
            IF (Char = 0) THEN EXIT                     ' Break out if char is NULL
            Debug Char                                ' Otherwise print it
        NEXT
    endif
RETURN

[HenrikOlsson]

Thanks for stepping in Richard, I should've mentioned my example was for 18F series of course. Yeah, the padding... It's a tradeoff, either waste memory or waste some time :-)

In your code I see

if (CTEMP.highbyte==0) || (CTEMP.highbyte ==0) then

I suppose one of those should be CTEMP.lowbyte, right?

[richard]

I suppose one of those should be CTEMP.lowbyte, right?

̶y̶e̶s̶ ̶,̶ ̶c̶o̶p̶y̶ ̶p̶a̶s̶t̶e̶ ̶t̶r̶a̶p̶ ̶f̶o̶r̶ ̶t̶h̶e̶ ̶i̶n̶o̶b̶s̶e̶r̶v̶a̶n̶t̶

its a pity the the forum edit restraints are so limiting

needs to be this , adding lowbyte breaks it
if (CTEMP.highbyte==0) then

[richard]

adding lowbyte breaks it

i remember it now , if you really want to be sparing with flash space odd length strings must not have the ,0 termination
the assembler adds the 0 for odd lengths automatically. the code then needs to check lowbyte for 0-ness

if you add the ,0 you wind up with 3 nulls in a row to account for hence only a check of highbyte works