PIC18F6621-I/PT Microchip Technology Inc., PIC18F6621-I/PT Datasheet - Page 145

• 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

14.0
The Timer3 module timer/counter has the following
features:
• 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
REGISTER 14-1:
 2005 Microchip Technology Inc.
(two 8-bit registers: TMR3H and TMR3L)
TIMER3 MODULE
bit 7
bit 6,3
bit 5-4
bit 2
bit 1
bit 0
T3CON: TIMER3 CONTROL REGISTER
RD16: 16-bit Read/Write Mode Enable bit
1 = Enables register read/write of Timer3 in one 16-bit operation
0 = Enables register read/write of Timer3 in two 8-bit operations
T3CCP2:T3CCP1: Timer3 and Timer1 to CCPx Enable bits
11 = Timer3 and Timer4 are the clock sources for ECCP1 through CCP5
10 = Timer3 and Timer4 are the clock sources for ECCP3 through CCP5;
01 = Timer3 and Timer4 are the clock sources for ECCP2 through CCP5;
00 = Timer1 and Timer2 are the clock sources for ECCP1 through CCP5
T3CKPS1:T3CKPS0: Timer3 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
T3SYNC: Timer3 External Clock Input Synchronization Control bit
(Not usable if the system clock comes from Timer1/Timer3)
When TMR3CS = 1:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
When TMR3CS = 0:
This bit is ignored. Timer3 uses the internal clock when TMR3CS = 0.
TMR3CS: Timer3 Clock Source Select bit
1 = External clock input from Timer1 oscillator or T13CKI
0 = Internal clock (F
TMR3ON: Timer3 On bit
1 = Enables Timer3
0 = Stops Timer3
bit 7
Legend:
R = Readable bit
-n = Value at POR
R/W-0
RD16
(on the rising edge after the first falling edge)
Timer1 and Timer2 are the clock sources for ECCP1 and ECCP2
Timer1 and Timer2 are the clock sources for ECCP1
T3CCP2
R/W-0
OSC
PIC18F6525/6621/8525/8621
T3CKPS1
/4)
R/W-0
W = Writable bit
‘1’ = Bit is set
T3CKPS0
R/W-0
Figure 14-1 is a simplified block diagram of the Timer3
module.
Register 14-1 shows the Timer3 Control register. This
register controls the operating mode of the Timer3
module and sets the CCP/ECCP clock source.
Register 12-1 shows the Timer1 Control register. This
register controls the operating mode of the Timer1
module, as well as contains the Timer1 oscillator
enable bit (T1OSCEN) which can be a clock source for
Timer3.
T3CCP1
R/W-0
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
T3SYNC
R/W-0
TMR3CS
x = Bit is unknown
R/W-0
DS39612B-page 143
TMR3ON
R/W-0
bit 0