PIC18F4520-I/P Microchip Technology Inc., PIC18F4520-I/P Datasheet - Page 130

• Manufacturer Part Number: PIC18F4520-I/P
• Description: 40 Pin, 32 KB Flash, 1536 RAM, 36 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F4520-I/P

• A/d Inputs: 13-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 10 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 36
• Interface: I2C/SPI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 40-pin PDIP
• Programmable Memory: 32K Bytes
• Ram Size: 1.5K Bytes
• Speed: 40 MHz
• Timers: 1-8-bit, 3-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

PIC18F2420/2520/4420/4520
12.1
Timer1 can operate in one of these modes:
• Timer
• Synchronous Counter
• Asynchronous Counter
The operating mode is determined by the clock select
bit, TMR1CS (T1CON<1>). When TMR3CS is cleared
(= 0), Timer1 increments on every internal instruction
FIGURE 12-1:
FIGURE 12-2:
DS39631A-page 128
Note 1: When enable bit, T1OSCEN, is cleared, the inverter and feedback resistor are turned off to eliminate power drain.
T1OSO/T13CKI
Note 1: When enable bit, T1OSCEN, is cleared, the inverter and feedback resistor are turned off to eliminate power drain.
T1OSO/T13CKI
Timer1 Operation
T1OSI
T1OSI
T1OSCEN
T1CKPS1:T1CKPS0
T1SYNC
TMR1ON
Timer1 Oscillator
Timer1 Oscillator
T1OSCEN
TIMER1 BLOCK DIAGRAM
TIMER1 BLOCK DIAGRAM (16-BIT READ/WRITE MODE)
T1CKPS1:T1CKPS0
T1SYNC
TMR1ON
(1)
(1)
TMR1CS
TMR1CS
(CCP Special Event Trigger)
Clear TMR1
(CCP Special Event Trigger)
Clear TMR1
Clock
Internal
F
Clock
F
Internal
OSC
OSC
/4
/4
Preliminary
On/Off
1
0
1
0
Timer1 Clock Input
Timer1 Clock Input
Prescaler
1, 2, 4, 8
Prescaler
1, 2, 4, 8
cycle (Fosc/4). When the bit is set, Timer1 increments
on every rising edge of the Timer1 external clock input
or the Timer1 oscillator, if enabled.
When Timer1 is enabled, the RC1/T1OSI and RC0/
T1OSO/T13CKI pins become inputs. This means the
values of TRISC<1:0> are ignored and the pins are
read as ‘0’.
2
2
TMR1L
TMR1L
8
Sleep Input
Synchronize
Sleep Input
8
Synchronize
Detect
Detect
High Byte
High Byte
TMR1H
TMR1
TMR1
8
 2004 Microchip Technology Inc.
8
8
Internal Data Bus
1
0
1
0
Read TMR1L
Write TMR1L
on Overflow
on Overflow
TMR1IF
TMR1IF
Set
Set
Timer1
On/Off
Timer1
On/Off