HSEROUT using STR modifier - length parameter as variable not working

[flotulopex]

Hi there,

I'm using HSEROUT with the STR modifier and I can't find the way to set the number of characters "\n" in a variable instead.

While this works:

HSEROUT [STR BalBuffer\40,26,13]

...this doesn't:

BalCount VAR BYTE
BalCount = 40
HSEROUT [STR BalBuffer\BalCount,26,13]

It is to mention that it does compile without error in both cases.

I didn't try this one, but according to some other post (from Bruce in 2005), DEBUG/DEBUGIN seem to accept a variable for the charater value.

Is this a limitation for the STR modifier (= it has to be a number) in HSEROUT or is there a way to make it work with a variable?

[HenrikOlsson]

I don't know and I can't test/try if your code right now but a simple workaround would be

For i = 0 to BalCount   '  (Or possibly BalCount-1)
  HSEROUT [BalBuffer]
NEXT
HSEROUT [26,13]

[flotulopex]

Thanks Henrik,

I went this way already but so it is correct, the number of characters cannot be replaced by a variable.

Strange....

[HenrikOlsson]

Which device are you using?

I compiled two different version and looked at the .lst and with my limited understanding of assembly I'd say it "should work"

First, HSEROUT [STR Buffer\16]

         movlw   low (010h)
         movwf   R4 + 1
         movlw   low (low (HSEROUTJ))
         movwf   R8
         clrf    (R8) + 1
         clrf    R2 + 1
         movlw   low (low (_Buffer))
         call    SEROUT2STRN

Here it takes the literal 16 and moves it to the low byte (I think) of system variable R4.

Second, HSEROUT [STR Buffer\Length]

         movf    _Length, W
         movwf   R4 + 1
         movlw   low (low (HSEROUTJ))
         movwf   R8
         clrf    (R8) + 1
         clrf    R2 + 1
         movlw   low (low (_Buffer))
         call    SEROUT2STRN

Here it takes the Length variable, and loads THAT to the low byte (I think) of system variable R4.

In the actual serout macro it then decrements R4 to determine when it's done.

[Ioannis]

Page 47 of the manual says "STR must be followed by a backslash and a number that specifies how many
characters (bytes) to collect."

So, as I understand it, it should be a number, not a variable.

If you want to change that on the fly, then Henrik's loop is the way to go.

Ioannis

[richard]

it works for me

 ;pic18f26k22 tx  demo
#CONFIG
  CONFIG  FOSC = INTIO67
  CONFIG  PLLCFG = OFF
  CONFIG  PRICLKEN = OFF
  CONFIG  FCMEN = OFF
  CONFIG  IESO = OFF
  CONFIG  PWRTEN = OFF
  CONFIG  BOREN = SBORDIS
  CONFIG  BORV = 190
  CONFIG  WDTEN = ON
  CONFIG  WDTPS = 32768
  CONFIG  CCP2MX = PORTC1
  CONFIG  PBADEN = OFF
  CONFIG  CCP3MX = PORTB5
  CONFIG  HFOFST = ON
  CONFIG  T3CMX = PORTC0
  CONFIG  P2BMX = PORTB5
  CONFIG  MCLRE = EXTMCLR
  CONFIG  STVREN = ON
  CONFIG  LVP = OFF
  CONFIG  XINST = OFF
  CONFIG  DEBUG = OFF
  CONFIG  CP0 = OFF
  CONFIG  CP1 = OFF
  CONFIG  CP2 = OFF
  CONFIG  CP3 = OFF
  CONFIG  CPB = OFF
  CONFIG  CPD = OFF
  CONFIG  WRT0 = OFF
  CONFIG  WRT1 = OFF
  CONFIG  WRT2 = OFF
  CONFIG  WRT3 = OFF
  CONFIG  WRTC = OFF
  CONFIG  WRTB = OFF
  CONFIG  WRTD = OFF
  CONFIG  EBTR0 = OFF
  CONFIG  EBTR1 = OFF
  CONFIG  EBTR2 = OFF
  CONFIG  EBTR3 = OFF
  CONFIG  EBTRB = OFF
#ENDCONFIG
  
  






define OSC 8


DEFINE DEBUG_REG PORTB  
DEFINE DEBUG_BIT 7
DEFINE DEBUG_BAUD 9600 
DEFINE DEBUG_MODE 0
DEFINE HSER_TXSTA 20h
DEFINE HSER_BAUD 9600
trisb=$7f 
OSCCON = $60   ;  OSC 8
anselc = 0
BalBuffer VAR BYTE[60]
BalCount VAR BYTE
latb.7=1
for   BalCount= 0 to 59
BalBuffer[BalCount]=BalCount+"0"
next
BalBuffer[59]=0
pause 2000
debug "ready",13,10






















BalCount = 40
HSEROUT [STR BalBuffer\BalCount,13,10]
debug   STR BalBuffer\BalCount,13,10
debug "full load",13,10
debug   STR BalBuffer,13,10
end

[richard]

or even

BalCount = 40HSEROUT [STR BalBuffer\BalCount,13,10]
debug   STR BalBuffer\BalCount,13,10
debug "full load",13,10
debug   STR BalBuffer,13,10
HSEROUT [STR BalBuffer,13,10]




for   BalCount= 0 to 40
HSEROUT [STR BalBuffer\BalCount,13,10]
next
end

[Ioannis]

Unfortunately Charles Leo is not monitoring this forum. I 'll make a post on support.melabs.com to clarify this, since the manual is not very clear on the matter.

I 'd rather be 100% sure that this is trusted all the time on all MCU's.

Ioannis

[flotulopex]

Which device are you using?

It's the one I always use: 16F690.

[flotulopex]

it works for me

Well, I'll give it a try with a 18F1220 when I'm back home tonight.

[richard]

it fails of course for more than 255 chrs

BalBuffer VAR BYTE[300]
BalCount VAR word
latb.7=1
clear
for   BalCount= 0 to 59
BalBuffer[BalCount]=BalCount+"0"
next


for   BalCount= 1 to 59
BalBuffer[BalCount+60]=BalCount+"0"
next
for   BalCount= 1 to 59
BalBuffer[BalCount+120]=BalCount+"0"
next
for   BalCount= 1 to 59
BalBuffer[BalCount+180]=BalCount+"0"
next
for   BalCount= 1 to 59
BalBuffer[BalCount+240]=BalCount+"0"
next
BalBuffer[0]=13
BalBuffer[60]=13
BalBuffer[120]=13
BalBuffer[180]=13
BalBuffer[240]=13
pause 2000
debug "ready",13,10




BalCount = 40
HSEROUT ["40 ",STR BalBuffer\BalCount,13,10]
debug   "40 ",STR BalBuffer\BalCount,13,10
debug "full load "
debug   STR BalBuffer,13,10
HSEROUT ["full load ",STR BalBuffer,13,10]




BalCount = 255
HSEROUT ["255 ",STR BalBuffer\BalCount,13,10]
HSEROUT [13,10]
HSEROUT ["260"]
BalCount = 260
HSEROUT [STR BalBuffer\BalCount,13,10]
end

[HenrikOlsson]

it fails of course for more than 255 chrs

Of course, since the macro only uses the low byte of R4 to index the array. That would also make it fail when using a constant >255.

In any case, the "example" posted in the first place had a BYTE sized variable with a value of 40 and everything we've seen this far is that it should (and ideed does, for 18F at least) work. I think I compiled for 16F628 when I looked at the .lst yesterday.

flotulopex,
You're going to have to post code that we can just compile, assemble and program into a chip that shows the problem.

[flotulopex]

flotulopex,
You're going to have to post code that we can just compile, assemble and program into a chip that shows the problem.

Yup, I will do so asap.... Sorry, didn't have much time yesterday.

[Ioannis]

Charles replied:

Yes, I believe it can be trusted with a variable. I've used this form to receive a variable number of characters based on a length parameter received immediately prior to the string:

[wait($80),length,STR idstring\length]

So officially it is valid syntax.

Ioannis

[flotulopex]

For now, here a my two test programs with 16F690 and 18F1220.

Surprisingly (to me), both accept the STR length as variable in the 3 ways I'm using it (HSEROUT, SEROUT2 and DEBUG).

I'll go back to my current program and try again....