PIC16C770 Microchip Technology Inc., PIC16C770 Datasheet - Page 49

• Manufacturer Part Number: PIC16C770
• Description: 18/20-pin, 8-bit Cmos Microcontrollers With 10/12-bit A/d
• Manufacturer: Microchip Technology Inc.

6.0
The Timer1 module timer/counter has the following fea-
tures:
• 16-bit timer/counter
• Readable and writable (Both registers)
• Internal or external clock select
• Interrupt on overflow from FFFFh to 0000h
• RESET from ECCP module trigger
Timer1 has a control register, shown in Register 6-1.
Timer1 can be enabled/disabled by setting/clearing
control bit TMR1ON (T1CON<0>).
Figure 6-2 is a simplified block diagram of the Timer1
module.
REGISTER 6-1:
2002 Microchip Technology Inc.
(Two 8-bit registers; TMR1H and TMR1L)
TIMER1 MODULE
bit 7-6
bit 5-4
bit 3
bit 2
bit 1
bit 0
TIMER1 CONTROL REGISTER (T1CON: 10h)
Unimplemented: Read as '0'
T1CKPS<1:0>: Timer1 Input Clock Prescale Select bits
11 = 1:8 Prescale value
10 = 1:4 Prescale value
01 = 1:2 Prescale value
00 = 1:1 Prescale value
T1OSCEN: Timer1 Oscillator Enable Control bit
1 = Oscillator is enabled
0 = Oscillator is shut off
T1SYNC: Timer1 External Clock Input Synchronization Control bit
TMR1CS = 1:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
TMR1CS = 0:
This bit is ignored. Timer1 uses the internal clock when TMR1CS = 0.
TMR1CS: Timer1 Clock Source Select bit
1 = External clock from pin RB6/T1OSO/T1CKI /P1C (on the rising edge)
0 = Internal clock (F
TMR1ON: Timer1 On bit
1 = Enables Timer1
0 = Stops Timer1
Legend:
R = Readable bit
- n = Value at POR
bit 7
Note 1: The oscillator inverter and feedback resistor are turned off to eliminate power drain.
U-0
—
U-0
—
OSC
(1)
/4)
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC
R/W-0
W = Writable bit
’1’ = Bit is set
R/W-0
Additional information on timer modules is available in
the PICmicro™ Mid-Range MCU Family Reference
Manual, (DS33023).
6.1
Timer1 can operate in one of these modes:
• As a timer
• As a synchronous counter
• As an asynchronous counter
The Operating mode is determined by the clock select
bit, TMR1CS (T1CON<1>).
In Timer mode, Timer1 increments every instruction
cycle. In Counter mode, it increments on every rising
edge of the external clock input.
PIC16C717/770/771
Timer1 Operation
R/W-0
U = Unimplemented bit, read as ‘0’
’0’ = Bit is cleared
R/W-0
x = Bit is unknown
TMR1CS TMR1ON
R/W-0
DS41120B-page 47
R/W-0
bit 0