Ra5/An4/Ss - Microchip Technology PIC16F87X Manual

PIC16F87X
FIGURE 1-2: PIC16F874 AND PIC16F877 BLOCK DIAGRAM
Device Program
FLASH
PIC16F874 4K
PIC16F877 8K
FLASH
Program
Memory
Program
14
Bus
Instruction reg
Instruction
Decode &
Control
Timing
Generation
OSC1/CLKIN
OSC2/CLKOUT
Timer0
Data EEPROM
Note 1: Higher order bits are from the STATUS register.
DS30292B-page 6
Data Memory Data
EEPROM
192 Bytes 128 Bytes
368 Bytes 256 Bytes
13
Program Counter
8 Level Stack
(13-bit)
7
Direct Addr
8
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
Brown-out
Reset
In-Circuit
Debugger
Low-Voltage
Programming
MCLR V , V
DD SS
Timer1 Timer2
Synchronous
CCP1,2
Serial Port
8
Data Bus
RAM
File
Registers
RAM Addr (1)
9
Addr MUX
Indirect
8
Addr
FSR reg
STATUS reg
3
MUX
ALU
8
W reg
Parallel Slave Port
10-bit A/D
USART
PORTA
RA0/AN0
RA1/AN1
RA2/AN2/V
REF
RA3/AN3/V
REF
RA4/T0CKI

RA5/AN4/SS

PORTB
RB0/INT
RB1
RB2
RB3/PGM
RB4
RB5
RB6/PGC
RB7/PGD
PORTC
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
PORTD
RD7/PSP7:RD0/PSP0
PORTE
RE0/AN5/RD
RE1/AN6/WR
RE2/AN7/CS
© 1999 Microchip Technology Inc.
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