Using variables in embedded asm code?

[jadiflow]

Hi,

I am trying to read the contents of a PIC timer register into a variable bMains_period I defined in Flowcode. Tried several ways to address the variable, with _FCV_ or FCV_ or just _ prepended, no success. Always get an ' undefined symbol' error message.

This is the code fragment:

Code: Select all

#asm
// read T0
banksel TMR0
move TMR0, 0
movwf FCV_bMains_period
#endasm

What am I missing?

[kersing]

Variable names are all upper case. So TesT would be FCV_TEST (for a global variable) or FCL_TEST (for a local variable)

[jadiflow]

I did try that, no joy:

Code: Select all

#asm
// read T0
banksel T0
move T0, 0
movwf FCV_BMAINS_PERIOD
#endasm

eDD SMS-1 freq test.c: 533: (876) syntax error
eDD SMS-1 freq test.c: 534: (800) undefined symbol "FCV_BMAINS_PERIOD"
(908) exit status = 1
(908) exit status = 1

Byte bMains_period IS defined; I use it elsewhere in the program with no issues.

Jan

[kersing]

Assuming your are using FC7 things are a bit more complicated:

For local variables within a macro the variable name seems to be:
c:FCM_<macroname>@FCM_<upper case variable name>
(This applies to local variables in the main macro as well)

For global variables:
c:_FCV_<upper case variable name>

If you want to check for your code, make sure it compiles to chip (disable any code generating compile errors), open de generated <project name>.AS file and search for the variable name.

[jadiflow]

I only have global variables (no parameter passing), and the c: prefix doesn't work in my assembly block within the C block.

Anyway, how is one to know all this?? I looked in the help file for C-block and there's a nice video going not much further than showing how to drag a C block onto the flowchart. Looked like FC4 or FC5, 2014. Duh.

There's a reason why I paid for FC4, FC5, FC6, FC7 - I have no ambition to dive into C or assembly.

I know, not your fault Kersing, but it's frustrating.

Jan Didden

[LeighM]

Is there any reason you need to use asm?
You could do this in C, in a C icon block...

Code: Select all

FCV_BMAINS_PERIOD = TMR0;

[jadiflow]

Yes that seems to work. Thanks.

Jan Didden
Linear Audio