PIC18F6621-I/PT Microchip Technology Inc., PIC18F6621-I/PT Datasheet - Page 133

• 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

11.0
The Timer0 module has the following features:
• Software selectable as an 8-bit or
• Readable and writable
• Dedicated 8-bit software programmable prescaler
• Clock source selectable to be external or internal
• Interrupt-on-overflow from FFh to 00h in 8-bit
• Edge select for external clock
REGISTER 11-1:
 2005 Microchip Technology Inc.
16-bit timer/counter
mode and FFFFh to 0000h in 16-bit mode
TIMER0 MODULE
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2-0
T0CON: TIMER0 CONTROL REGISTER
Legend:
R = Readable bit
-n = Value at POR
bit 7
TMR0ON: Timer0 On/Off Control bit
1 = Enables Timer0
0 = Stops Timer0
T08BIT: Timer0 8-bit/16-bit Control bit
1 = Timer0 is configured as an 8-bit timer/counter
0 = Timer0 is configured as a 16-bit timer/counter
T0CS: Timer0 Clock Source Select bit
1 = Transition on T0CKI pin
0 = Internal instruction cycle clock (CLKO)
T0SE: Timer0 Source Edge Select bit
1 = Increment on high-to-low transition on T0CKI pin
0 = Increment on low-to-high transition on T0CKI pin
PSA: Timer0 Prescaler Assignment bit
1 = TImer0 prescaler is not assigned. Timer0 clock input bypasses prescaler.
0 = Timer0 prescaler is assigned. Timer0 clock input comes from prescaler output.
T0PS2:T0PS0: Timer0 Prescaler Select bits
111 = 1:256 Prescale value
110 = 1:128 Prescale value
101 = 1:64 Prescale value
100 = 1:32 Prescale value
011 = 1:16 Prescale value
010 = 1:8
001 = 1:4
000 = 1:2
TMR0ON
R/W-1
Prescale value
Prescale value
Prescale value
T08BIT
R/W-1
PIC18F6525/6621/8525/8621
R/W-1
T0CS
W = Writable bit
‘1’ = Bit is set
R/W-1
T0SE
Figure 11-1 shows a simplified block diagram of the
Timer0 module in 8-bit mode and Figure 11-2 shows a
simplified block diagram of the Timer0 module in 16-bit
mode.
The T0CON register (Register 11-1) is a readable and
writable register that controls all the aspects of Timer0,
including the prescale selection.
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
R/W-1
PSA
T0PS2
R/W-1
x = Bit is unknown
T0PS1
R/W-1
DS39612B-page 131
T0PS0
R/W-1
bit 0