Datasheet

PIC18F6525/6621/8525/8621
DS39612C-page 10  2003-2013 Microchip Technology Inc.
FIGURE 1-2: PIC18F8525/8621 BLOCK DIAGRAM
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
Instruction
Decode and
Control
OSC1/CLKI
OSC2/CLKO
Brown-out
Reset
EUSART1Comparator
MSSP
EUSART2
Timing
Generation
10-bit
ADC
Data Latch
Data RAM
(3.8 Kbytes)
Address Latch
Address<12>
12
Bank0, FBSR
FSR0
FSR1
FSR2
inc/dec
logic
Decode
4
12 4
PCH PCL
PCLATH
8
31 Level Stack
Program Counter
PRODLPRODH
8 x 8 Multiply
W
8
BITOP
8
8
ALU<8>
8
Test Mode
Select
Address Latch
Program Memory
(48/64 Kbytes)
Data Latch
20
21
16
8
8
8
Table Pointer<21>
inc/dec logic
21
8
Data Bus<8>
Table Latch
8
IR
12
3
ROM Latch
PCLATU
PCU
Precision
Reference
Band Gap
PORTH
RH0/A16:RH3/A19
(4)
PORTJ
RJ6/LB
RJ7/UB
RJ5/CE
RJ4/BA0
RJ3/WRH
RJ2/WRL
RJ0/ALE
RJ1/OE
Timer2Timer1 Timer3 Timer4Timer0
Note 1: ECCP2/P2A are multiplexed with RC1 when CCP2MX is set; with RE7 when CCP2MX is cleared and the device is configured in
Microcontroller mode; or with RB3 when CCP2MX is cleared in all other program memory modes.
2: P1B/P1C/P3B/P3C are multiplexed with RE6:RE3 when ECCPMX is set and with RH7:RH4 when ECCPMX is not set.
3: RG5 is multiplexed with MCLR
and is only available when the MCLR Resets are disabled.
4: External memory interface pins are multiplexed with PORTD (AD7:AD0), PORTE (AD15:AD8) and PORTH (A19:A16).
CCP4 CCP5
RH7/AN15/P1B
(2)
RH6/AN14/P1C
(2)
RH5/AN13/P3B
(2)
RH4/AN12/P3C
(2)
LVD
PORTA
PORTB
PORTC
RA4/T0CKI
RA5/AN4/LVDIN
RB0/INT0/FLT0
RC0/T1OSO/T13CKI
RC2/ECCP1/P1A
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX1/CK1
RC7/RX1/DT1
RA3/AN3/VREF+
RA2/AN2/VREF-
RA1/AN1
RA0/AN0
RB1/INT1
PORTD
RB2/INT2
RB3/INT3/ECCP2
(1)
/P2A
(1)
PORTE
PORTG
RG0/ECCP3/P3A
RG1/TX2/CK2
RG2/RX2/DT2
RG3/CCP4/P3D
RG4/CCP5/P1D
RE6/AD14/P1B
(2,4)
RE7/AD15/ECCP2
(1)
/P2A
(1,4)
RE5/AD13/P1C
(2,4)
RE4/AD12/P3B
(2,4)
RE3/AD11/P3C
(2,4)
RE2/AD10/CS/P2B
(4)
RE0/AD8/RD/P2D
(4)
RE1/AD9/WR/P2C
(4)
OSC2/CLKO/RA6
PORTF
RF6/AN11
RF7/SS
RF5/AN10/CVREF
RF4/AN9
RF3/AN8
RF2/AN7/C1OUT
RF0/AN5
RF1/AN6/C2OUT
RB4/KBI0
RB5/KBI1/PGM
RB6/KBI2/PGC
RB7/KBI3/PGD
RC1/T1OSI/ECCP2
(1)
/P2A
(1)
VDD, VSS
MCLR
(3)
ECCP2 ECCP3 ECCP1
MCLR/VPP/RG5
(3)
RD7/AD7/PSP7:
BOR
AD15:AD0, A19:16
(4)
System Bus Interface
Data
EEPROM
RD0/AD0/PSP0
(4)