PIC18F47J53 Datasheet, PDF (209/586 Pages) Microchip Technology – 28/44-Pin, High-Performance USB Microcontrollers with nanoWatt XLP Technology

PIC18F47J53 FAMILY
13.0 TIMER1 MODULE
The Timer1 timer/counter module incorporates these
features:
• Software selectable operation as a 16-bit timer or
counter
• Readable and writable 8-bit registers (TMR1H
and TMR1L)
• Selectable clock source (internal or external) with
device clock or Timer1 oscillator internal options
• Interrupt-on-overflow
• Reset on ECCP Special Event Trigger
• Device clock status flag (SOSCRUN)
• Timer with gated control
Figure 13-1 displays a simplified block diagram of the
Timer1 module.
The module incorporates its own low-power oscillator
to provide an additional clocking option. The Timer1
oscillator can also be used as a low-power clock source
for the microcontroller in power-managed operation.
Timer1 is controlled through the T1CON Control
register (Register 13-1). It also contains the Timer1
Oscillator Enable bit (T1OSCEN). Timer1 can be
enabled or disabled by setting or clearing control bit,
TMR1ON (T1CON<0>).
The FOSC clock source (TMR1CS<1:0> = 01) should not
be used with the ECCP capture/compare features. If the
timer will be used with the capture or compare features,
always select one of the other timer clocking options.
REGISTER 13-1: T1CON: TIMER1 CONTROL REGISTER (ACCESS FCDh)
R/W-0
TMR1CS1
bit 7
R/W-0
TMR1CS0
R/W-0
T1CKPS1
R/W-0
T1CKPS0
R/W-0
T1OSCEN
R/W-0
T1SYNC
R/W-0
RD16
R/W-0
TMR1ON
bit 0
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
bit 7-6
bit 5-4
bit 3
bit 2
bit 1
bit 0
TMR1CS<1:0>: Timer1 Clock Source Select bits
10 = Timer1 clock source is the T1OSC or T1CKI pin
01 = Timer1 clock source is the system clock (FOSC)⁽¹⁾
00 = Timer1 clock source is the instruction clock (FOSC/4)
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 Source Select bit
When TMR1CS<1:0> = 10:
1 = Power up the Timer1 crystal driver and supply the Timer1 clock from the crystal output
0 = Timer1 crystal driver is off, Timer1 clock is from the T1CKI input pin⁽²⁾
When TMR1CS<1:0> = 0x:
1 = Power up the Timer1 crystal driver
0 = Timer1 crystal driver is off⁽²⁾
T1SYNC: Timer1 External Clock Input Synchronization Select bit
TMR1CS<1:0> = 10:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
TMR1CS<1:0> = 0x:
This bit is ignored. Timer1 uses the internal clock when TMR1CS<1:0> = 0x.
RD16: 16-Bit Read/Write Mode Enable bit
1 = Enables register read/write of Timer1 in one 16-bit operation
0 = Enables register read/write of Timer1 in two 8-bit operations
TMR1ON: Timer1 On bit
1 = Enables Timer1
0 = Stops Timer1
Note 1:
2:
The FOSC clock source should not be selected if the timer will be used with the ECCP capture/compare features.
The Timer1 oscillator crystal driver is powered whenever T1OSCEN (T1CON<3>) or T3OSCEN
(T3CON<3>) = 1. The circuit is enabled by the logical OR of these two bits. When disabled, the inverter and
feedback resistor are disabled to eliminate power drain. The TMR1ON and TMR3ON bits do not have to be
enabled to power up the crystal driver.
 2010 Microchip Technology Inc.
Preliminary
DS39964B-page 209