PIC16F628-04/SS Microchip Technology, PIC16F628-04/SS Datasheet - Page 47

• Manufacturer Part Number: PIC16F628-04/SS
• Description: IC MCU FLASH 2KX14 COMP 20SSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F628-04/SS

• Core Size: 8-Bit
• Program Memory Size: 3.5KB (2K x 14)
• Core Processor: PIC
• Speed: 4MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 16
• Program Memory Type: FLASH
• Eeprom Size: 128 x 8
• Ram Size: 224 x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 20-SSOP
• Controller Family/series: PIC16F
• No. Of I/o's: 16
• Eeprom Memory Size: 128Byte
• Ram Memory Size: 224Byte
• Cpu Speed: 4MHz
• No. Of Timers: 3
• Package: 20SSOP
• Device Core: PIC
• Family Name: PIC16
• Maximum Speed: 4 MHz
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 16
• Interface Type: SCI/USART
• Number Of Timers: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT20SS-1 - SOCKET TRANSITION 18DIP 20SSOPAC164307 - MODULE SKT FOR PM3 28SSOPAC164018 - MODULE SKT PROMATEII 20SSOP
• Data Converters: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

6.3.1
The prescaler assignment is fully under software
control (i.e., it can be changed “on the fly” during
program execution). Use the instruction sequences,
shown in Example 6-1, when changing the prescaler
assignment from Timer0 to WDT, to avoid an
unintended device RESET.
EXAMPLE 6-1:
TABLE 6-1:
 2003 Microchip Technology Inc.
01h
0Bh/8Bh/
10Bh/18Bh
81h, 181h
85h
Legend:
Note 1: Shaded bits are not used by TMR0 module.
Address
BCF
CLRWDT
CLRF
BSF
MOVLW
MOVWF
CLRWDT
MOVLW
MOVWF
BCF
2: Option is referred by OPTION_REG in MPLAB.
— = Unimplemented locations, read as ‘0’, u = unchanged, x = unknown
SWITCHING PRESCALER
ASSIGNMENT
TMR0
INTCON
OPTION
TRISA
STATUS, RP0
TMR0
STATUS, RP0
'00101111’b
OPTION_REG
'00101xxx’b
OPTION_REG
STATUS, RP0
Name
REGISTERS ASSOCIATED WITH TIMER0
(2)
CHANGING PRESCALER
(TIMER0→WDT)
Timer0 module register
TRISA7
RBPU
Bit 7
GIE
;Skip if already in
;Bank 0
;Clear WDT
;Clear TMR0 & Prescaler
;Bank 1
;These 3 lines
;(5, 6, 7)
;are required only
;if desired PS<2:0>
;are
;000 or 001
;Set Postscaler to
;desired WDT rate
;Return to Bank 0
INTEDG
TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 1111 1111 1111 1111
Bit 6
PEIE
T0CS
Bit 5
T0IE
Preliminary
T0SE
Bit 4
INTE
Bit 3
RBIE
PSA
To change prescaler from the WDT to the TMR0
module use the sequence shown in Example 6-2. This
precaution must be taken even if the WDT is disabled.
EXAMPLE 6-2:
CLRWDT
BSF
MOVLW
MOVWF
BCF
Bit 2
T0IF
PS2
STATUS, RP0
b'xxxx0xxx' ;Select TMR0, new
OPTION_REG
STATUS, RP0
Bit 1
INTF
PS1
CHANGING PRESCALER
(WDT→TIMER0)
Bit 0
RBIF
PS0
PIC16F62X
;Clear WDT and
;prescaler
;prescale value and
;clock source
xxxx xxxx uuuu uuuu
0000 000x 0000 000u
1111 1111 1111 1111
Value on
POR
DS40300C-page 45
All Other
Value on
RESETS