PIC16F874-20/L Microchip Technology, PIC16F874-20/L Datasheet - Page 136

• Manufacturer Part Number: PIC16F874-20/L
• Description: IC MCU FLASH 4KX14 EE 44PLCC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F874-20/L

• Core Size: 8-Bit
• Program Memory Size: 7KB (4K 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: 128 x 8
• Ram Size: 192 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 44-PLCC
• Controller Family/series: PIC16F
• No. Of I/o's: 33
• Eeprom Memory Size: 128Byte
• Ram Memory Size: 192Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 192 B
• Interface Type: MSSP, PSP, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 33
• Number Of Timers: 3
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 70 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: 0 C
• On-chip Adc: 10 bit, 8 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164309 - MODULE SKT FOR PM3 44PLCC444-1001 - DEMO BOARD FOR PICMICRO MCUDVA16XL441 - ADAPTER DEVICE ICE 44PLCC309-1040 - ADAPTER 44-PLCC ZIF TO 40-DIP309-1039 - ADAPTER 44-PLCC TO 40-DIPDV007003 - PROGRAMMER UNIVERSAL PROMATE II
• Lead Free Status / Rohs Status: Details

PICmicro MID-RANGE MCU FAMILY
8.6
DS31008A-page 8-14
Initialization
Example 8-4
is the value to write into the interrupt enable register.
Example 8-5
before they are used. For debugging ease, it may help if macros are placed in other files that are
included at assembly time. This allows the source to be viewed without all the clutter of the
required macros. These files must be included before the macro is used, but it simplifies debug-
ging, if all include files are done at the top of the source file.
Example 8-7
saving and restoring of registers before the execution of the interrupt code.
Example 8-4: Initialization and Enabling of Interrupts
Example 8-5: Register Saving / Restoring as Macros
PIE1_MASK1
PUSH_MACRO
;
POP_MACRO
MOVWF
SWAPF
MOVWF
ENDM
SWAPF
MOVWF
SWAPF
SWAPF
ENDM
:
:
CLRF
CLRF
CLRF
BSF
MOVLW
MOVWF
BCF
BSF
shows the initialization and enabling of device interrupts, where PIE1_MASK1 value
shows a typical Interrupt Service Routine structure. This ISR uses macros for the
shows how to create macro definitions for functions. Macros must be defined
EQU B‘01101010’
STATUS
INTCON
PIR1
STATUS, RP0
PIE1_MASK1
PIE1
STATUS, RP0
INTCON, GIE
MACRO
W_TEMP
STATUS,W
STATUS_TEMP
MACRO
STATUS_TEMP,W
STATUS
W_TEMP,F
W_TEMP,W
; Bank0
; Disable interrupts and clear some flags
; Clear all flag bits
; Bank1
; This is the initial masking for PIE1
;
; Bank0
; Enable Interrupts
; This Macro Saves register contents
; Copy W to a Temporary Register
;
; Swap STATUS nibbles and place
;
; Save STATUS to a Temporary register
;
; End this Macro
; This Macro Restores register contents
; Swap original STATUS register value
;
; Restore STATUS register from
;
; Swap W_Temp nibbles and return
;
; Swap W_Temp to W to restore original
;
; End this Macro
; This is the Interrupt Enable
;
regardless of current bank
into W register
in Bank0
into W (restores original bank)
W register
value to W_Temp
W value without affecting STATUS
Register mask value
Example 8-6
1997 Microchip Technology Inc.
shows this structure.