Rainbow Electronics AT89C5131 - Manual (Page 3)

3
AT89C5131
4136A–USB–03/03
Block Diagram
Notes: 1. Alternate function of Port 1
2. Alternate function of Port 3
3. Alternate function of Port 4 (Alternate function of Port 4 on PLCC52, under evaluation)
Timer 0 INT
RAM
256x8
T0 T1
Rx
D
Tx
D
WR
RD
EA
PSEN
ALE
XTAL2
XTAL1
EUART
CPU
Timer 1
INT
1
Ctrl
INT
0
(2)
(2)
C51
CORE
(2) (2) (2) (2)
Port 0
P0
Port 1 Port 2 Port 3
Parallel I/O Ports & Ext. Bus
P1 P2 P3
XRAM
1Kx8
PCA
RST
Watch
Dog
CEX ECI VS
S
VDD
(2) (2)
(1) (1)
Timer2
T2
EX
T2
(1) (1)
Port 4
P4
32Kx8 Flash
+
BRG
USB
D - D +
VREF
Regu- Key
Board
KIN
lator
AVSS
EEPROM
4Kx8
SPI
MI
S
O
MOS
I
SC
K
(1) (1) (1)
SS
(1)
AVDD