In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Rsadeika wrote:

I am still using the Guenther code, the listing that I have is functional, I have some remarks through out the code, so if somebody notices a glaring mistake, please make me aware of it.
 

Now, I have a question about the proper usage of IRC_CAL.

 

The DEVICE OSC4MHZ selects the SX internal RC, and you get three choices of IRC_CAL IRC_SLOW, IRC_4MHZ, and IRC_FAST. In the data sheet it states something about a +-8%, I assume that IRC_SLOW would be a calibration at -8%, and IRC_FAST would be a calibration of +8%. What kind of calibration does IRC_4MHS get? So, I guess you get a warning here, do not use this setting if you will be using this to send a rocket to Mars.

 

The DEVICE OSCHSx selects one of the High speed crystal/res. choices, and as turns out you get to use an IRC_CAL setting, also. So, when you select IRC_SLOW or IRC_FAST, what exactly do you get? When you leave out the IRC_CAL setting, the compiler gives a warning that it is using the default IRQ_SLOW setting. When I am using a freq 50_000_000, in the run window it just shows that the freq of the program is 50_000_000. Does the same warning apply here, do not use for rocket science.

 

I guess my question is for the more experienced programmers, down the road, will this come in handy, the usage of IRQ_CAL. At this point I am sort of missing the utility of the IRC_CAL setting. A couple of examples could be in order, if possible.

 

Ray

Thanks in advance

 

****CODE

;;;
;; Tut003.src
;;;

device sx52
device oschs3       ;High speed crystal, 1MHz - 75MHz
;IRC_CAL IRC_FAST   ;Real life utility still undecided
freq 50_000_000

;****
;device osc4mhz      ;This uses the SX internal RC
;IRC_CAL IRC_FAST    ;Specific for 4MHz selection
                     ;Selections are IRC_CAL IRC_FAST,
                     ;IRC_4MHZ, IRC_SLOW
;freq 4_000_000      ;Can use different freq's up to 4MHz
;****

reset Main                 ;Label where the program starts

;Data area         ;I lean towards structure, this notation 
                   ;is for me to make things a little easier
 
 org $0A            ;This is the starting point for Data
                           ;and Code, the compiler sorts it out
                           ;SX52 -> $0A, SX28 -> $08
                           ;                         
Counter1 ds 1              ;Remember code can be placed here
Counter2 ds 1              ;also, the compiler distinguishes 
Counter3 ds 1              ;between variables and code
;End of data

;Code area
 org $0             ;Code start position on reset
Main
 mov w,#$1f         ;This is SX52 specific -> TRIS_
 mov m,w
 mov !rd,#%11111110 ;Set rd.0 to output

Loop
 
 decsz Counter1      ;Counter1 is a byte, descsz starts at 255
                            ;and decrements until it hits 0
   jmp Loop
 decsz Counter2
   jmp Loop
 decsz Counter3
   jmp Loop
 clrb rd.0           ;Turn on the LED

Loop1
      decsz Counter1
   jmp Loop1
 decsz Counter2
   jmp Loop1
 decsz Counter3
   jmp Loop1
 setb rd.0           ;Turn off the LED
 jmp Loop 

 

jmp $      ;I like to use this to end my code,
           ;at this point it is in an endless loop.

end        ;End of source code, remmarks can be placed 
           ;here after 'end'. The compiler treats 
           ;it as text and is ignored.

---------- End of Message ----------


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