RFPIC12C509AG Datasheet, PDF (21/104 Pages) Microchip Technology – 18/20-Pin 8-Bit CMOS Microcontroller with UHF ASK/FSK Transmitter

rfPIC12C509AG/509AF
4.4 OPTION Register
The OPTION register is a 8-bit wide, write-only register
which contains various control bits to configure the
Timer0/WDT prescaler and Timer0.
By executing the OPTION instruction, the contents of
the W register will be transferred to the OPTION regis-
ter. A RESET sets the OPTION<7:0> bits.
FIGURE 4-4:
OPTION REGISTER
Note:
Note:
If TRIS bit is set to ‘0’, the wake-up on
change and pull-up functions are disabled
for that pin (i.e., note that TRIS overrides
OPTION control of GPPU and GPWU).
If the T0CS bit is set to ‘1’, GP2 is forced to
be an input even if TRIS GP2 = ‘0’.
W-1
W-1
W-1
W-1
W-1
W-1
W-1
GPWU GPPU T0CS T0SE
PSA
PS2
PS1
bit7
6
5
4
3
2
1
bit 7:
GPWU: Enable wake-up on pin change (GP0, GP1, GP3)
1 = Disabled
0 = Enabled
bit 6:
GPPU: Enable weak pull-ups (GP0, GP1, GP3)
1 = Disabled
0 = Enabled
bit 5:
T0CS: Timer0 clock source select bit
1 = Transition on T0CKI pin
0 = Transition on internal instruction cycle clock, Fosc/4
bit 4:
T0SE: Timer0 source edge select bit
1 = Increment on high to low transition on the T0CKI pin
0 = Increment on low to high transition on the T0CKI pin
bit 3:
PSA: Prescaler assignment bit
1 = Prescaler assigned to the WDT
0 = Prescaler assigned to Timer0
bit 2-0: PS2:PS0: Prescaler rate select bits
Bit Value Timer0 Rate WDT Rate
000
1:2
1:1
001
1:4
1:2
010
1:8
1:4
011
1 : 16
1:8
100
1 : 32
1 : 16
101
1 : 64
1 : 32
110
1 : 128
1 : 64
111
1 : 256
1 : 128
W-1
PS0
bit0
W = Writable bit
U = Unimplemented bit
- n = Value at POR Reset
Reference Table 4-1 for
other RESETS.
© 2001 Microchip Technology Inc.
Preliminary
DS70031A-page 19