PIC18F6621-I/PT Microchip Technology Inc., PIC18F6621-I/PT Datasheet - Page 146

• Manufacturer Part Number: PIC18F6621-I/PT
• Description: 64 PIN, 64 KB FLASH, 3840 RAM, 52 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F6621-I/PT

• A/d Inputs: 12-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 10 MIPS
• Eeprom Memory: 1024 Bytes
• Input Output: 54
• Interface: I2C/SPI/UART/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 64-pin TQFP
• Programmable Memory: 64K Bytes
• Ram Size: 3.8K Bytes
• Speed: 40 MHz
• Timers: 2-8-bit, 3-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

PIC18F6525/6621/8525/8621
14.1
Timer3 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, TMR3CS (T3CON<1>).
FIGURE 14-1:
FIGURE 14-2:
DS39612B-page 144
Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
Note 1: When the T1OSCEN bit is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
Set TMR3IF Flag bit
on Overflow
T1OSO/
T13CKI
T1OSI
Timer3 Operation
Data Bus<7:0>
Write TMR3L
Read TMR3L
T1OSO/
T13CKI
T1OSI
TMR3IF
Overflow
Interrupt
Flag bit
TIMER3 BLOCK DIAGRAM
TIMER3 BLOCK DIAGRAM CONFIGURED IN 16-BIT READ/WRITE MODE
T1OSC
8
TMR3H
High Byte
T1OSC
TMR3H
Timer3
8
To Timer1 Clock Input
Oscillator
Enable
T1OSCEN
8
TMR3
TMR3L
Oscillator
Enable
T1OSCEN
(1)
8
TMR3L
CLR
(1)
Internal
Clock
F
CLR
OSC
/4
TMR3ON
F
Internal
Clock
On/Off
OSC
TMR3CS
When TMR3CS = 0, Timer3 increments every instruc-
tion cycle. When TMR3CS = 1, Timer3 increments on
every rising edge of the Timer1 external clock input or
the Timer1 oscillator, if enabled.
When the Timer1 oscillator is enabled (T1OSCEN is
set), the RC1/T1OSI and RC0/T1OSO/T13CKI pins
become inputs. That is, the TRISC<1:0> value is
ignored and the pins are read as ‘0’.
Timer3 also has an internal “Reset input”. This Reset
can be generated by the ECCP module (Section 14.0
“Timer3 Module”).
ECCP Special Event Trigger
T3CCPx
1
0
/4
TMR3ON
On/Off
T3CKPS1:T3CKPS0
TMR3CS
1
0
T3SYNC
T3CCPx
Prescaler
ECCP Special Event Trigger
1, 2, 4, 8
T3CKPS1:T3CKPS0
0
1
T3SYNC
2
Prescaler
1, 2, 4, 8
0
1
 2005 Microchip Technology Inc.
2
Synchronized
Clock Input
Synchronize
Sleep Input
Synchronized
det
Clock Input
Synchronize
Sleep Input
det