PIC12CE67 Microchip Technology, PIC12CE67 Datasheet - Page 35

• Manufacturer Part Number: PIC12CE67
• Description: 8-Pin/ 8-Bit CMOS Microcontroller with A/D Converter and EEPROM Data Memory
• Manufacturer: Microchip Technology

7.3.1
The prescaler assignment is fully under software con-
trol, i.e., it can be changed “on the fly” during program
execution.
EXAMPLE 7-1:
TABLE 7-1:
Address Name
01h
0Bh/8Bh INTCON
81h
85h
Legend: x = unknown, u = unchanged, - = unimplemented locations read as '0'. Shaded cells are not used by Timer0.
1998 Microchip Technology Inc.
Note:
BCF
CLRF
BSF
CLRWDT
MOVLW
MOVWF
BCF
SWITCHING PRESCALER ASSIGNMENT
TMR0
OPTION GPPU INTEDG
TRIS
STATUS, RP0
TMR0
STATUS, RP0
b'xxxx1xxx'
OPTION_REG
STATUS, RP0
To avoid an unintended device RESET, the
following instruction sequence (shown in
Example 7-1) must be executed when
changing the prescaler assignment from
Timer0 to the WDT. This sequence must
be followed even if the WDT is disabled.
REGISTERS ASSOCIATED WITH TIMER0
Timer0 module’s register
CHANGING PRESCALER
(TIMER0 WDT)
Bit 7
GIE
—
;Bank 0
;Clear TMR0 & Prescaler
;Bank 1
;Clears WDT
;Select new prescale
;value & WDT
;Bank 0
PEIE
Bit 6
—
TRIS5
T0CS
Bit 5
T0IE
TRIS4
T0SE
INTE
Bit 4
Preliminary
TRIS3
GPIE
Bit 3
PSA
To change prescaler from the WDT to the Timer0 mod-
ule use the sequence shown in Example 7-2.
EXAMPLE 7-2:
CLRWDT
BSF
MOVLW
MOVWF
BCF
TRIS2
Bit 2
T0IF
PS2
TRIS1
INTF
Bit 1
PS1
STATUS, RP0 ;Bank 1
b'xxxx0xxx' ;Select TMR0, new
OPTION_REG
STATUS, RP0 ;Bank 0
CHANGING PRESCALER
(WDT TIMER0)
TRIS0
GPIF
Bit 0
PIC12CE67X
PS0
;Clear WDT and
;prescaler
;prescale value and
;clock source
xxxx xxxx
0000 000x
1111 1111
--11 1111
Value on
POR
DS40181B-page 35
uuuu uuuu
0000 000u
1111 1111
--11 1111
Value on
all other
Resets