16LF1824 strange problem

[midali]

Something is strange. Now it work with the same variable in init and in main loops. Yesterday I tried a many time and don't worked.
@ richard : thx for your suggestions
Here is working code :

#CONFIG
        __CONFIG _CONFIG1, _FCMEN_OFF & _FOSC_INTOSC & _WDTE_OFF & _MCLRE_OFF & _CP_ON & _IESO_OFF & _BOREN_OFF & _PWRTE_OFF
        __CONFIG _CONFIG2, _PLLEN_OFF & _STVREN_OFF & _LVP_OFF
#ENDCONFIG

DEfine  OSC 4 
OSCCON = %01101010   'sets the internal oscillator to 4Mhz



ADCON0 = %00000000    
ADCON1 = %00000000     
FVRCON = %11000010     'turn fixed voltage reference on & set it to 2.048V (last two bits set the voltage ...01 =1.024V,10=2.048
CM1CON0 = 0   ' COMPARATORS OFF
CM1CON1 = 0
CM2CON0 = 0   ' COMPARATORS OFF
CM2CON1 = 0    
CPSCON0 = 0   'CAPACTIVE SENSE MODULE OFF
RCSTA.7  = 0   'SERIAL PORT OFF

TRISA   = %00000000
TRISC   = %00000100    
ANSELA = %00000000
ANSELC = %00000000

OPTION_REG.7 = 0
WPUA  =  %00000000

PORTA = 0
PORTC = 0 

Symbol front  = PORTA.4


x      var  byte
varb   var  byte
divf   var  byte

x        = 0
varb   = 0
divf    = 0

pause 100

init:
pulsin portc.2 , 1, varb
 if (varb < 140) or (varb > 160) then init
 pause 100
 pulsin portc.2 , 1, varb
 if (varb < 140) or (varb > 160) then init
 if (varb > 140) and (varb < 160) then goto beep
goto init

beep:      
hpwm 1 , 10, 3000
    high front
    pause 80
    low front
    pause 200
hpwm 1 , 5, 1200
    high front
    pause 80
    low front
    pause 200
hpwm 1 , 10, 3000
    high front
    pause 80
    low front
 

'************************************************************
main:
pulsin portc.2 , 1, varb
hpwm 1 , x, 1954 

'=======================miss signal=========================
if varb < 50 then
     varb = 150
     x=0
     low front
endif
'============================================================

'========================front===============================
if varb> 160  then
        high front
    if varb > 190 then varb = 190
        divf=255*(varb-160)/30
    if x > 255 then x = 255
    if divf > 255 then divf = 255            
    if divf >x then x=x+2
    if divf <x then x=x-6
endif
'============================================================

'==================== stay ==================================
if varb < 160 and varb > 140 then
    low front
    x= 0 
endif
'=============================================================

'==========================light==============================
if varb < 140 and varb > 50 then
     high PORTA.0
else
    low PORTA.0
endif
goto main
end

[EarlyBird2]

Well done you have made a lot of progress. Just a couple of small points

DEfine  OSC 4

should be

DEFINE OSC 4

if only to make it more readable.

OSCCON = %01101010   'sets the internal oscillator to 4Mhz

not that it matters in this case and simply to further understanding.

_FOSC_INTOSC directs the internal oscillator to be used
OSCCON = %01101000 sets the oscillator defined by FOSC to 4Mhz

OSCCON = %01101010 switches to the internal oscillator and sets it to 4Mhz

So what difference does it make? It looks like there are two methods for achieving the same thing.

[Dave]

"not that it matters in this case and simply to further understanding." I beg your pardon? When using the internal oscillator, "OSCCON" register is the only way to select the internal oscillator speed. Unless it is set it will default to 500Khz.

[EarlyBird2]

"not that it matters in this case and simply to further understanding." I beg your pardon? When using the internal oscillator, "OSCCON" register is the only way to select the internal oscillator speed. Unless it is set it will default to 500Khz.

I am asking a question not stating anything why say "I beg your pardon?" did I say something wrong.

You are correct Dave, about the speed did I say otherwise?

The question is why are there two methods to select the internal oscillator and what is the difference. In the code FOSC is used to select the internal oscillator and also OSCCON is used to select the internal oscillator.

[mackrackit]

FOSC in the configs tells the type of oscillator used. In this case internal.

OSCCON sets the speed of the internal with bits 6-3.

Bit 1-0 of OSCCON is for two-speed start-up. If internal is selected in the config, two-speed start-up is disabled.

[EarlyBird2]

From the datasheet.

5.4.1 TWO-SPEED START-UP MODE
CONFIGURATION
Two-Speed Start-up mode is configured by the
following settings:
• IESO (of the Configuration Word 1) = 1; Internal/
External Switchover bit (Two-Speed Start-up
mode enabled).
• SCS (of the OSCCON register) = 00.
• FOSC<2:0> bits in the Configuration Word 1
configured for LP, XT or HS mode.

Which I take to mean that SCS has to be 00 for Two-Speed Start-up to work. I am not certain this is the same as

Bit 1-0 of OSCCON is for two-speed start-up. If internal is selected in the config, two-speed start-up is disabled.

This section of the datasheet is the source of the issue

5.2.2.1 HFINTOSC
The High-Frequency Internal Oscillator (HFINTOSC) is
a factory calibrated 16 MHz internal clock source. The
frequency of the HFINTOSC can be altered via
software using the OSCTUNE register (Register 5-3).
The output of the HFINTOSC connects to a postscaler
and multiplexer (see Figure 5-1). One of nine
frequencies derived from the HFINTOSC can be
selected via software using the IRCF<3:0> bits of the
OSCCON register. See Section 5.2.2.7 “Internal
Oscillator Clock Switch Timing” for more information.
The HFINTOSC is enabled by:
• Configure the IRCF<3:0> bits of the OSCCON
register for the desired HF frequency, and
• FOSC<2:0> = 100, or
• Set the System Clock Source (SCS) bits of the
OSCCON register to ‘1x’.

Which as I read it states either set FOSC<2:0> = 100 or SCS to '1x' but not both. Yet in the code

#CONFIG
        __CONFIG _CONFIG1, _FCMEN_OFF & _FOSC_INTOSC & _WDTE_OFF & _MCLRE_OFF & _CP_ON & _IESO_OFF & _BOREN_OFF & _PWRTE_OFF
        __CONFIG _CONFIG2, _PLLEN_OFF & _STVREN_OFF & _LVP_OFF
#ENDCONFIG

DEfine  OSC 4 
OSCCON = %01101010   'sets the internal oscillator to 4Mhz

Both are set.

Obviously the code works and setting SCS to '1x' is having no detrimental effect in this case. Am I interpreting the datasheet wrong?

[richard]

best way to view it
from the data sheet

bit 1-0 SCS<1:0>: System Clock Select bits
1x = Internal oscillator block
01 = Timer1 oscillator
00 = Clock determined by FOSC<2:0> in Configuration Word 1.

when FOSC<2:0> = 100 is equivalent to 1x = Internal oscillator block ie they both set the same option (logical or )

but watch out if you want the pll engaged