PIC17C756A MICROCHIP [Microchip Technology], PIC17C756A Datasheet - Page 97

• Manufacturer Part Number: PIC17C756A
• Description: High-Performance 8-bit CMOS EPROM Microcontrollers with 10-bit A/D
• Manufacturer: MICROCHIP [Microchip Technology]

12.0
The Timer0 module consists of a 16-bit timer/counter,
TMR0. The high byte is register TMR0H and the low
byte is register TMR0L. A software programmable 8-bit
prescaler makes Timer0 an effective 24-bit overflow
timer. The clock source is software programmable as
either the internal instruction clock, or an external clock
on the RA1/T0CKI pin. The control bits for this module
are in register T0STA (Figure 12-1).
REGISTER 12-1: T0STA REGISTER (ADDRESS: 05h, UNBANKED)
2000 Microchip Technology Inc.
bit 7
bit 6
bit 5
bit 4-1
bit 0
TIMER0
Legend:
R = Readable bit
- n = Value at POR Reset
bit 7
INTEDG: RA0/INT Pin Interrupt Edge Select bit
This bit selects the edge upon which the interrupt is detected.
1 = Rising edge of RA0/INT pin generates interrupt
0 = Falling edge of RA0/INT pin generates interrupt
T0SE: Timer0 Clock Input Edge Select bit
This bit selects the edge upon which TMR0 will increment.
When T0CS = 0 (External Clock):
1 = Rising edge of RA1/T0CKI pin increments TMR0 and/or sets the T0CKIF bit
0 = Falling edge of RA1/T0CKI pin increments TMR0 and/or sets the T0CKIF bit
When T0CS = 1 (Internal Clock):
Don’t care
T0CS: Timer0 Clock Source Select bit
This bit selects the clock source for TMR0.
1 = Internal instruction clock cycle (T
0 = External clock input on the T0CKI pin
T0PS3:T0PS0: Timer0 Prescale Selection bits
These bits select the prescale value for TMR0.
Unimplemented: Read as ’0’
INTEDG
T0PS3:T0PS0 Prescale Value
R/W-0
0000
0001
0010
0011
0100
0101
0110
0111
1xxx
R/W-0
T0SE
1:1
1:2
1:4
1:8
1:16
1:32
1:64
1:128
1:256
R/W-0
T0CS
W = Writable bit
’1’ = Bit is set
CY
T0PS3
R/W-0
)
T0PS2
R/W-0
U = Unimplemented bit, read as ‘0’
’0’ = Bit is cleared
T0PS1
R/W-0
PIC17C7XX
x = Bit is unknown
T0PS0
R/W-0
DS30289B-page 97
U-0
—
bit 0