PIC16F877-04E/PT Microchip Technology, PIC16F877-04E/PT Datasheet - Page 186

• Manufacturer Part Number: PIC16F877-04E/PT
• Description: IC MCU FLASH 8KX14 EE 44TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F877-04E/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 4MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 33
• Program Memory Size: 14KB (8K x 14)
• 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 ~ 125°C
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: PIC16F87704E/PT

PICmicro MID-RANGE MCU FAMILY
DS31012A-page 12-6
Example 12-2
in
Example 12-2:
Writing a 16-bit value to the 16-bit TMR1 register is straight forward. First the TMR1L register is
cleared to ensure that there are many Timer1 clock/oscillator cycles before there is a rollover into
the TMR1H register. The TMR1H register is then loaded, and finally the TMR1L register is loaded.
Example 12-3
Example 12-3:
; All interrupts are disabled
;
; TMR1L may have rolled over between the read of the high and low bytes.
; Reading the high and low bytes now will read a good value.
;
; Re-enable the Interrupt (if required)
CONTINUE
; All interrupts are disabled
; Re-enable the Interrupt (if required)
CONTINUE
Example
MOVF
MOVWF
MOVF
MOVWF
MOVF
SUBWF
BTFSC
GOTO
MOVF
MOVWF
MOVF
MOVWF
CLRF
MOVLW
MOVWF
MOVLW
MOVWF
12-1. This is useful if the timer cannot be stopped.
shows a routine to read the 16-bit timer value with experiencing the issues shown
shows this:
TMR1H, W
TMPH
TMR1L, W
TMPL
TMR1H, W
TMPH,
STATUS,Z
CONTINUE
TMR1H, W
TMPH
TMR1L, W
TMPL
TMR1L
HI_BYTE
TMR1H, F
LO_BYTE
TMR1H, F
Reading a 16-bit Free-Running Timer
Writing a 16-bit Free Running Timer
W
; Read high byte
;
; Read low byte
;
; Read high byte
; Sub 1st read with 2nd read
; Is result = 0
; Good 16-bit read
; Read high byte
;
; Read low byte
;
; Continue with your code
; Clear Low byte, Ensures no
;
; Value to load into TMR1H
; Write High byte
; Value to load into TMR1L
; Write Low byte
; Continue with your code
rollover into TMR1H
1997 Microchip Technology Inc.