PIC16F877A-I/ML Microchip Technology, PIC16F877A-I/ML Datasheet - Page 176

• Manufacturer Part Number: PIC16F877A-I/ML
• Description: IC MCU FLASH 8KX14 A/D 44QFN
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F877A-I/ML

• Core Size: 8-Bit
• Program Memory Size: 14KB (8K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 33
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 368 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-QFN
• Controller Family/series: PIC16F
• No. Of I/o's: 33
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 368Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 368 B
• Interface Type: I2C, SPI, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 33
• Number Of Timers: 1 x 16 bit
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163022, DV164120
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT44QFN2 - SOCKET TRAN ICE 44QFN/40DIPAC164322 - MODULE SOCKET MPLAB PM3 28/44QFN444-1001 - DEMO BOARD FOR PICMICRO MCU
• Lead Free Status / Rohs Status: Details

PICmicro MID-RANGE MCU FAMILY
11.6.1
DS31011A-page 11-8
Lines 2 and 3 do
NOT have to be
included if the final
desired prescale
value is other than
1:1. If 1:1 is final
desired value, then a
temporary prescale
value is set in lines 2
and 3 and the final
prescale value will
be set in lines 10
and 11.
Switching Prescaler Assignment
The prescaler assignment is fully under software control, i.e., it can be changed “on the fly” during
program execution.
In
final desired prescaler is other then 1:1. If the final prescaler value is to be 1:1, then a temporary
prescale value is set (other than 1:!), and the final prescale value is set in the last modification of
OPTION_REG.
Example 11-1: Changing Prescaler (Timer0 WDT)
To change prescaler from the WDT to the Timer0 module use the sequence shown in
Example
Example 11-2: Changing Prescaler (WDT Timer0)
1)
2)
3)
4)
5)
6)
7)
8)
9)
10) MOVLW
11) MOVWF
12) BCF
Example
BSF
MOVLW
MOVWF
BCF
CLRF
BSF
MOVLW
MOVWF
CLRWDT
CLRWDT
BSF
MOVLW
MOVWF
BCF
11-2.
Note:
11-1, the first modification of the OPTION_REG does not need to be included if the
STATUS, RP0
b'xx0x0xxx'
OPTION_REG
STATUS, RP0
TMR0
STATUS, RP1
b'xxxx1xxx'
OPTION_REG
b'xxxx1xxx'
OPTION_REG
STATUS, RP0
STATUS, RP0
b'xxxx0xxx'
OPTION_REG
STATUS, RP0
To avoid an unintended device RESET, the following instruction sequence
(shown in
assignment from Timer0 to the WDT. This sequence must be followed even if
the WDT is disabled.
Example
;Bank1
;Select clock source and prescale value of
;other than 1:1
;Bank0
;Clear TMR0 and prescaler
;Bank1
;Select WDT, do not change prescale value
;
;Clears WDT and prescaler
;Select new prescale value and WDT
;
;Bank0
; Clear WDT and prescaler
; Bank1
; Select TMR0, new prescale
; value and clock source
; Bank0
11-1) must be executed when changing the prescaler
1997 Microchip Technology Inc.