PIC16CR54C
By executing the OPTION instruction, the contents of
the W register will be transferred to the OPTION
register. A RESET sets the OPTION<5:0> bits.
4.4
OPTION Register
The OPTION register is
register which contains various control bits to
configure the Timer0/WDT prescaler and Timer0.
a
6-bit wide, write-only
FIGURE 4-4: OPTION REGISTER
U-0
—
U-0
—
6
W-1
T0CS
5
W-1
T0SE
4
W-1
PSA
3
W-1
PS2
2
W-1
PS1
1
W-1
PS0
W
U
= Writable bit
= Unimplemented bit
bit7
bit0
- n = Value at POR reset
bit 7-6: Unimplemented.
bit 5:
bit 4:
bit 3:
T0CS: Timer0 clock source select bit
1 = Transition on T0CKI pin
0 = Internal instruction cycle clock (CLKOUT)
T0SE: Timer0 source edge select bit
1 = Increment on high-to-low transition on T0CKI pin
0 = Increment on low-to-high transition on T0CKI pin
PSA: Prescaler assignment bit
1 = Prescaler assigned to the WDT (not implemented on PIC16C52)
0 = Prescaler assigned to Timer0
bit 2-0: PS2:PS0: Prescaler rate select bits
Bit Value
Timer0 Rate WDT Rate (not implemented on PIC16C52)
000
001
010
011
100
101
110
111
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256
1 : 1
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
DS40191A-page 16
Preliminary
1998 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
