Embedded Strings in your Code Space

[mytekcontrols]

If you look at the last code example you may be asking yourself "Hey isn't that the same thing as HSEROUT ["This is a string"]?"

Well... yes it is, sort of. What I really see to be accomplished here, has more to do with creating the framework for a customizable message string handling Function, then just mimicing an already available PicBasic Pro function. For testing purposes, it is just easier to send it out unaltered through the RS232 port. Ulimately, it will hopefully evolve into a great way to send either message strings, data, or both to any device you wish. While at the same time doing it in a way that is more like a built-in PicBasic Pro function.

A great example of what this could be used for, is imagine that you are interfaced to a device that would accept message strings via RS232, but always requires special commands to precede the message. Using what has already been developed here, all that would be required is to add these commands within the printSTR code (same as what was done for the carriage return and linefeed). Then every time you send a message such as @ SendStr "This is a string" the pre commands would be automatically sent as well.

Even better still, imagine if you were interfaced to several different devices or gateways, each one having special communication requirements (I2C, SPI, One-Wire, RS232, ect.). Every protocol could concievably be supported within the printSTR code, thereby allowing you to broadcast simultaneously to all devices via the single line SendStr function. Pretty cool huh!

We are only scratching the surface as to the possibilities.

[Darrel Taylor]

Hiya Michael,

And for my next installment of things you can change with the program you already have working ....

Sometimes I go crazy with the macro's. But I kinda like this one.

'--[ Initialise USART for specified baud rate at current OSC speed ]------------
ASM
USART_Init  macro  Baud
    clrf    TXSTA, 0
_SPBRG = (OSC * 1000000) / 16 / Baud - 1     ; calc SPBRG @ High baud rate
    if _SPBRG > 255                          ; if SPBRG is too high
_SPBRG = (OSC * 1000000) / 64 / Baud - 1     ; calc for Low baud rate
        bcf   TXSTA, BRGH, 0                 ; Set BRGH to Low Speed
        if _SPBRG > 255
_SPBRG = 255
        endif
    else                                     
        bsf   TXSTA, BRGH, 0                 ; Set BRGH to High Speed
    endif
    bsf     TXSTA, TXEN, 0                   ; Set Transmit Enable bit
    movlw   _SPBRG          
    movwf   SPBRG, 0                         ; load the calulated SPBRG
    movlw   B'10010000'                      ; enable USART
    movwf   RCSTA, 0
    endm
ENDASM

Now to initialize the USART all you have to do is this...

@ USART_Init 19200

It should work with any OSC setting and any valid baud rate.

-------------------------

>> Ulimately, it will hopefully evolve into a great way to send either message strings, data, or both to any device you wish.

I've also got some MAJOR changes that allow you to do the above quote. Haven't tested them completely yet, but they look promising.

Best regards,
   Darrel

[mytekcontrols]

I've also got some MAJOR changes that allow you to do the above quote. Haven't tested them completely yet, but they look promising.

Hey Darrel, I really think we got you hooked on this :-)
Which is perfectly fine by me, and will surely be fun to see what's in store.

Any good ideas on the best way to deal with the interrupt disable issue? I was reading up on this a bit, and it seems like some approaches could cause latency problems. I am also not 100% sure of which parts of the stack manipulation are no no's while an interrupt is occuring (in otherwords, is it only during the PUSH, or POP or both).

My particular interest will be to implement the "printSTR" in an I2C format, since a video chip I am working with requires this. It also has fussy timing requirements that appear to lower than even the standard device speed. to top it off I have 2 chips on board, so I am using independant clock lines and a shared SDA, since they both have identical addresses. Presently I have everything working with a custom PicBasic Pro I2C routine, but I suspect I'll need to implement this as an ASM routine if it is to be incorporated into the "printSTR" routine. Unless your MAJOR changes would allow for this.

BTW: I like the USART routine, it makes it very easy which we all love.

[mytekcontrols]

Darrel this incorporates your USART macro (works great):

DEFINE LOADER_USED 1    ' use for Boot Loader
DEFINE OSC 40   ' change to suit oscillator speed

'============================================
' Equates
'============================================

temp var byte   ' temporary storage for character

    Goto main   ' skip around Macros

'============================================
' Macros
'============================================
' Send String Macro (must be located prior to Main)
ASM
SendStr  macro Astring
    call _prntSTR
    data Astring,0
    endm
ENDASM

' USART Initialization Macro (must be located prior to Main)
' [ Initialize USART for specified baud rate at current OSC speed ]
ASM
USART_Init  macro  Baud
    clrf    TXSTA, 0
_SPBRG = (OSC * 1000000) / 16 / Baud - 1     ; calc SPBRG @ High baud rate
    if _SPBRG > 255                          ; if SPBRG is too high
_SPBRG = (OSC * 1000000) / 64 / Baud - 1     ; calc for Low baud rate
        bcf   TXSTA, BRGH, 0                 ; Set BRGH to Low Speed
        if _SPBRG > 255
_SPBRG = 255
        endif
    else                                     
        bsf   TXSTA, BRGH, 0                 ; Set BRGH to High Speed
    endif
    bsf     TXSTA, TXEN, 0                   ; Set Transmit Enable bit
    movlw   _SPBRG          
    movwf   SPBRG, 0                         ; load the calulated SPBRG
    movlw   B'10010000'                      ; enable USART
    movwf   RCSTA, 0
    endm
ENDASM

'============================================
' Main Program
'============================================
Main:
@ USART_Init 19200  ; set RS232 baudrate

' send messages through RS232
' format #1
@ SendStr "This is a string" 
@ SendStr "yet another string again"
@ SendStr "and one more time!"

' format #2
ASM
  SendStr "This is a string" 
  SendStr "yet another string again"
  SendStr "and one more time!"
ENDASM

Done:
   Goto Done        ' loop forever

'============================================
' String Extraction and Print Routines
'============================================
' print string code (locate anywhere)
ASM
_prntSTR
;copy return address to TBLPTR and then pop it off the stack
    movf    TOSU,W
    movwf   TBLPTRU
    movf    TOSH,W
    movwf   TBLPTRH
    movf    TOSL,W
    movwf   TBLPTRL
    POP

;TBLPTR should now be pointing to 1st character in string
Next_Char
    tblrd   *+              ; table read and post increment TBLPTR
    movff   TABLAT,_temp    ; fetch character from message string
    bra     Test_EOM        ; go test for EOM character
	
Continue                    ; If not EOM then...
    movf    _temp,W         ; move character into TXREG and...
    movwf   TXREG           ; send it!
    btfss   TXSTA,TRMT      ; has it been transmitted?
    goto    $-2             ; If not, keep checking
    bra     Next_Char       ; fetch next message character from table
	
Test_EOM
    movlw   .0              ; check for EOM character
    cpfseq  _temp,W         ; compare temp with w, if temp = 0 then end			
    bra     Continue        ; no EOM, so continue
    movlw   "\r"            ; move carriage return into TXREG and...
    movwf   TXREG           ; send it!
    btfss   TXSTA,TRMT      ; has it been transmitted?
    goto    $-2             ; If not, keep checking	
    movlw   "\n"            ; move line feed into TXREG and...
    movwf   TXREG           ; send it!
    btfss   TXSTA,TRMT      ; has it been transmitted?
    goto    $-2             ; If not, keep checking

;use incremented value of TBLPTR as new return address (push it)
    PUSH
    movf   TBLPTRU,W
    movwf   TOSU
    movf   TBLPTRH,W
    movwf   TOSH
    movf   TBLPTRL,W
    movwf   TOSL
    return                  ;finished with message, return to caller
ENDASM

[Darrel Taylor]

That's great Michael, glad you liked it. And it's good to have willing particpants around.

And, if you wanted more macro's... then I'm sure to make you happy today.

Oh boy, where to start.... I guess I'll start at the end result.

What this does is to allow the strings to be sent to up to 7 different "Destinations". Those destinations can be easily defined like this.

@  Make_Destination  HSER, _HSER_Send

This creates a Destination named "HSER", and everytime the program needs to send a character, it will call the _HSER_Send subroutine.

Each destination needs it's own subroutine to actually send the data. The character is placed in the temp variable before calling it. Here's one for HSER.

HSER_Send:
     While PIR1.4 = 0 : Wend
     TXREG = temp 
return

To make another Destination for the LCD, is just as easy...

@  Make_Destination  LCD,  _LCD_Send

LCD_Send:
    LCDOUT temp
Return

Now when using the SendStr macro, you can tell it which destination you want it to go to.

@ SendStr "This is a string", HSER
@ SendStr "1 for the LCD", LCD

You can even combine them to send the data to multiple Destinations.

@ SendStr "This is a string", HSER + LCD

Destination #8 is reserved for a CR,LF option that can be used like this...

@ SendStr "This is a string", HSER + CRLF

Of course, here's the one you were after...

@  Make_Destination  I2C,  _I2C_Send

I2C_Send:
     ' However you need to do it here...
RETURN

In order to make this work, I ripped up your code pretty bad. Sorry!

For instance, I got rid of the whole Pushing and Popping stuff. I hated to do that, but at least it solves the interrupt problem. The TBLPTR is now loaded from the SendStr macro so that it doesn't need to use the stack to get the address. Major changes to the prntSTR section too. It had all the USART stuff in there that had to come out. The Make_Destination and Director macro's are the real difference that allows the data to be re-directed. I'm sure there will be some questions on them, but for now I'll let you try to figure it out first.

Here's the whole thing.

SER2_TX      VAR  PORTE.0
SER2_Baud    CON  396
TRISB.6 = 1   ' Set USART TX pin to Output

temp         var  byte
Destination  VAR  BYTE

@CRLF = 0x080    ; Reserve destination #8 for CR,LF after string

'--[ Initialise USART for specified baud rate at current OSC speed ]------------
asm
USART_Init  macro  Baud
    clrf    TXSTA, 0
_SPBRG = (OSC * 1000000) / 16 / Baud - 1     ; calc SPBRG @ High baud rate
    if _SPBRG > 255                          ; if SPBRG is too high
_SPBRG = (OSC * 1000000) / 64 / Baud - 1     ; calc for Low baud rate
        bcf   TXSTA, BRGH, 0                 ; Set BRGH to Low Speed
        if _SPBRG > 255
_SPBRG = 255
        endif
    else                                     
        bsf   TXSTA, BRGH, 0                 ; Set BRGH to High Speed
    endif
    bsf     TXSTA, TXEN, 0                   ; Set Transmit Enable bit
    movlw   _SPBRG          
    movwf   SPBRG, 0                         ; load the calulated SPBRG
    movlw   B'10010000'                      ; enable USART
    movwf   RCSTA, 0
    endm
ENDASM

;----[Make_Destination]---- Compile Time Only - Does not use any Code space ----
ASM
DestinationCount = 0                              ; Global

Make_Destination  macro Nam, Sub
Nam = 1 << DestinationCount                       ; Generate a unique ID
Destination#v(DestinationCount) = Sub             ; Save Subroutines Address
DestinationCount += 1                             
    endm
ENDASM

;----[SendStr] -----------------------------------------------------------------
ASM
SendStr  macro Astring, Dest
  local TheStringData, BypassData
    goto   BypassData                             ; Jump over the data
TheStringData    
    data   Astring,0                              ; Place String Data here
BypassData
    MOVE?CB   Dest, _Destination
    MOVE?CB   low TheStringData, TBLPTRL          ; Load the address of 
    MOVE?CB   low (TheStringData >> 8), TBLPTRH   ;  TheStringData into
    MOVE?CB   low (TheStringData >> 16), TBLPTRU  ;      TABLPTR
    L?CALL    prntSTR
    if (Dest && CRLF) > 0
        L?CALL  _Send_CRLF
    endif
    endm
ENDASM

;----[ This macro will call each of the specified Destinations in sequence ]----
ASM    
Director  macro
  local counter
counter = 0
      while counter < DestinationCount
          btfsc  _Destination, counter
          CALL   Destination#v(counter)
counter += 1          
      endw
    endm    
ENDASM


;---[ These define the Destinations that will be called to output each byte ]---
;                                                     There is currently a  
;                    Name, _Subroutine                MAXimum of 7 destinations
@  Make_Destination  HSER, _HSER_Send
@  Make_Destination  SER2, _SER2_Send
@  Make_Destination  LCD,  _LCD_Send
@  Make_Destination  I2C,  _I2C_Send


Main:
@ USART_Init 19200
@ SendStr "This is a string", HSER + CRLF
@ SendStr "yet another string again", (HSER  + SER2 + CRLF)
@ SendStr "and one more time!", I2C
@ SendStr "1 for the LCD", LCD

Done:
   Goto Done

;-------------------------------------------------------------------------------
HSER_Send:
     While PIR1.4 = 0 : Wend
     TXREG = temp 
return

;-------------------------------------------------------------------------------
SER2_Send:
    SEROUT2  SER2_TX, SER2_Baud, [temp]
Return

;-------------------------------------------------------------------------------
LCD_Send:
    LCDOUT temp
Return

;-------------------------------------------------------------------------------
I2C_Send:
     ' However you need to do it here...
RETURN

;----[prntStr]------------------------------------------------------------------
ASM
;--- TBLPTR should be pointing to 1st character in string before calling -------
prntSTR
Next_Char
    tblrd   *+              ; table read and post increment TBLPTR
    movff   TABLAT,_temp    ; fetch character from message string
    bra     Test_EOM        ; go test for EOM character
Continue                    ; If not EOM then...
    Director                ; Send the byte to each specified destination
    bra     Next_Char       ; fetch next message character from table
Test_EOM
    movlw   .0              ; check for EOM character
    cpfseq  _temp,W         ; compare temp with w, if temp = 0 then end			
    bra     Continue        ; no EOM, so continue
    return                  ;finished with message, return to caller
endasm

;---[Send Carriage Return, Line feed to the dest's specified in last SendStr]---
Send_CRLF:
    temp = 13
    @ Director
    temp = 10
    @ Director
RETURN

end

Note that prntSTR and Send_CRLF must be at the end of the program for the Director to work properly.

Well, have fun, and I hope this is closer to what you were looking for.

Best regards,
Darrel

[mytekcontrols]

And, if you wanted more macro's... then I'm sure to make you happy today.

Wow! Am I ever! It'll keep me quite busy this week trying it out in my application.

In order to make this work, I ripped up your code pretty bad. Sorry!

For instance, I got rid of the whole Pushing and Popping stuff. I hated to do that, but at least it solves the interrupt problem.

I have no problem at all with this. At the time it was the only way I knew how to start heading in the direction I wanted to go. Perhaps it'll still be of use to someone, since there doesn't appear to be too much info out on the net showing actual application of this 18F series ability.

Major changes to the prntSTR section too. It had all the USART stuff in there that had to come out.

As you probably saw in my last code post, I had already ripped this out and gone ahead and used your USART initialize macro.

The Make_Destination and Director macro's are the real difference that allows the data to be re-directed. I'm sure there will be some questions on them, but for now I'll let you try to figure it out first.

Yes I do have questions, but I'll hold off until I have had ample time to digest it. And perhaps I wont if my brain can take it all in.

Well, have fun, and I hope this is closer to what you were looking for.

This is EXACTLY (and more) what I was looking for!
Thanks so very, very much,

[mister_e]

Here's my own version. Not as brilliant as all the above but allow to send String and numeric value. Have fun!
[html]
' ///////////////////////////////////|\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
' Embedded String and Data handling
' =================================
' Steve Monfette
' Mister E Enr
'
' This program show how to use/define/send a combination of String and Data
' to a PC terminal or else @9600 bauds.
'
' We can still use HSEROUT and do the same thing, of course but the
' following use another approach wich :
' 1. Allow to modify one or all string/data in a snap when needed.
' 2. Call a string many time only by calling his name with the macro.
' That is still more code efficient than if you create and use
' a specific SUBROUTINE.
'
' Also, if you compare this method to the use of multiple HSEROUT,
' you'll notice a slight difference in the size of the generated code.
'
' This program could also be usefull to send string/data to various device
' like I2C, LCD,...
' ///////////////////////////////////|\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

@ errorlevel 0,-207 ' avoid anoying MPASM error message
' -- found label after column 1 --

' PIC Definition
' ==============
' Done with an old & dusty PIC16F877 @ 20MHZ
'
DEFINE LOADER_USED 1
DEFINE OSC 20

' Hardware define
' ===============
'
TRISC=%10111111

' Serial Comm definition
' ======================
'
RCSTA=$90 ' Enable USART, continuous receive
TXSTA=$24 ' Enable transmit, BRGH=1
SPBRG=129 ' 9600 Bauds

' Variable definition
' ===================
'
Char var byte ' Character to be read/send
SAddr var word ' String adress pointer

' Software initialisation
' =======================
'
clear ' set all variable to 0
goto Start ' Skip any Macro And string Definition

' String Definition
' =================
' String must be defined as follow
' <label> dt <data>,0
'
' could also be
' <label> dt <data>
' dt <data>
' .........
' dt <data>,0
'
' Any String must be NULL terminated. Can contain text and numeric value
'
asm

s1 dt "String #1",13,10,0

s2 dt "String #2",13,10
dt "********************",13,10,0

s3 dt "String #3",13,10,0

s4 dt "String #4..... THE LAST ONE",13,10,0

endasm

' Macro Definition
' ================
'
' SendString:
' ===========
' This send the according string via USART
' Format:
' =======
' SendString <StringName>
'
asm
SendString macro StringLabel
CHK?RP _SAddr ; Reach the right BANK of SAddr
MOVE?CW StringLabel,_SAddr ; Store address of StringLabel in SAddr
L?CALL SendIt ; Send the string.
endm
endasm
@SendIt
Readcode SAddr, char ' Read character
if Char then ' if not NULL, send it
ASM
MOVE?BB _Char,TXREG ; Load TXREG with Char
IsFull
BIT?GOTO 0, PIR1, 4, IsFull ; Loop while TXREG is full
; The above is the same as
; IF PIR1.4=0 THEN GOTO IsFull
;
INCF _SAddr,1 ; Point to the next character
GOTO SendIt ; Do it again
ENDASM
endif
return


' /////////////////////////////////|\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
Start:
' /////////////////////////////////|\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
'
' Here we will send our data by using the above macro
'
@ SendString s1 ; Send string with label 's1'
@ SendString s2 ; Send string with label 's2'
@ SendString s3 ; Send string with label 's3'
@ SendString s4 ; Send string with label 's4'
pause 1500 ; wait a little bit
goto Start ; do it again
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