PIC14000-04 Microchip Technology, PIC14000-04 Datasheet - Page 18

• Manufacturer Part Number: PIC14000-04
• Description: 28-Pin Programmable Mixed Signal Controller
• Manufacturer: Microchip Technology

PIC14000
4.2.2.2
The OPTION register (Address 81h) is a readable and
writable register which contains various control bits to
configure the TMR0/WDT prescaler, TMR0, and the
weak pull-ups on PORTC<5:0>. Bit 6 is reserved.
FIGURE 4-4:
DS40122B-page 18
bit7
RCPU
R/W
OPTION REGISTER
R/W
r
OPTION REGISTER
T0CS T0SE
R/W
R/W
PSA
R/W
PS2 PS1
R/W R/W
T0SE: TMR0 source edge
T0CS: TMR0 clock source
1 = Transition on RC3/T0CKI pin
Reserved. This bit should be programmed as a ‘1’. Use of this bit as
general purpose read/write is not recommended since this may affect
upward compatibility with future products.
PSA: Prescaler assignment bit
0 = Internal instruction cycle clock (CLKOUT)
RCPU: PORTC pull-up enable
PS2:PS0
1 = Prescaler assigned to the WDT
0 = Prescaler assigned to TMR0
1 = Increment on high-to-low transition on RC3/T0CKI pin
0 = Increment on low-to-high transition on RC3/T0CKI pin
1 = PORTC pull-ups are disabled overriding any port latch value (RC<5:0> only)
0 = PORTC pull-ups are enabled by individual port-latch values (RC<5:0>)
PS0
R/W
Preliminary
bit0
PS2
PRESCALER VALUE
Register:
Address:
POR value:
0
0
0
0
1
1
1
1
PS1
Note:
0
0
1
1
0
0
1
1
OPTION
PS0
0
1
0
1
0
1
0
1
81h
FFh
To achieve a 1:1 prescaler assignment,
assign the prescaler to the WDT (PSA=1)
TMR0 RATE
W:
R:
U:
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256
Writable
Readable
Unimplemented.
Read as '0'
1996 Microchip Technology Inc.
WDT RATE
1 : 1
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128