PIC18F2221-E/SP Microchip Technology, PIC18F2221-E/SP Datasheet - Page 129

• Manufacturer Part Number: PIC18F2221-E/SP
• Description: 4KB, Flash, 512bytes-RAM, 25I/O, 8-bit Family,nanoWatt 28 SPDIP .300in TUBE
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F2221-E/SP

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 25
• Program Memory Size: 4KB (2K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 10x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 28-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: DVA18XP280 - DEVICE ADAPTER 18F2220 PDIP 28LD
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

12.0
The Timer0 module incorporates the following features:
• Software selectable operation as a timer or coun-
• Readable and writable registers
• Dedicated 8-bit, software programmable
• Selectable clock source (internal or external)
• Edge select for external clock
• Interrupt-on-overflow
REGISTER 12-1:
© 2009 Microchip Technology Inc.
ter in both 8-bit or 16-bit modes
prescaler
TIMER0 MODULE
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2-0
T0CON: TIMER0 CONTROL REGISTER
PIC18F2221/2321/4221/4321 FAMILY
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.
T0PS<2:0>: 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
R/W-1
T0CS
W = Writable bit
‘1’ = Bit is set
R/W-1
T0SE
The T0CON register (Register 12-1) controls all
aspects of the module’s operation, including the
prescale selection. It is both readable and writable.
A simplified block diagram of the Timer0 module in 8-bit
mode is shown in Figure 12-1. Figure 12-2 shows a
simplified block diagram of the Timer0 module in 16-bit
mode.
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
DS39689F-page 129
T0PS0
R/W-1
bit 0