Ra5/An4/Ss - Microchip Technology PIC16F87X Manual

PIC16F87X
FIGURE 1-2: PIC16F874 AND PIC16F877 BLOCK DIAGRAM
Program
Device
FLASH
PIC16F874 4K
PIC16F877 8K
FLASH
Program
Memory
Program
14
Bus
Instruction reg
Instruction
Decode &
Control
Timing
Generation
OSC1/CLKIN
OSC2/CLKOUT
Timer0 Timer1
Data EEPROM
CCP1,2
Note 1: Higher order bits are from the STATUS register.
DS30292D-page 6
Data
Data Memory
EEPROM
192 Bytes 128 Bytes
368 Bytes 256 Bytes
13
Program Counter
8 Level Stack
(13-bit)
RAM Addr
7
Direct Addr
8
3
Power-up
Timer
Oscillator
Start-up Timer
Power-on
8
Reset
Watchdog
Timer
Brown-out
Reset
In-Circuit
Debugger
Low-Voltage
Programming
MCLR V , V
DD SS
Timer2
Synchronous
Serial Port
8
PORTA
Data Bus
RAM
File
Registers
PORTB
(1)
9
Addr MUX
Indirect
8
Addr
FSR reg
STATUS reg
PORTC
MUX
ALU
W reg
PORTD
Parallel Slave Port
PORTE
10-bit A/D
USART
 1998-2013 Microchip Technology Inc.
RA0/AN0
RA1/AN1
RA2/AN2/V -
REF
RA3/AN3/V +
REF
RA4/T0CKI

RA5/AN4/SS

RB0/INT
RB1
RB2
RB3/PGM
RB4
RB5
RB6/PGC
RB7/PGD
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
RD0/PSP0
RD1/PSP1
RD2/PSP2
RD3/PSP3
RD4/PSP4
RD5/PSP5
RD6/PSP6
RD7/PSP7
RE0/AN5/RD
RE1/AN6/WR
RE2/AN7/CS