Rainbow Electronics AT83C21GC - Manual (Page 4)

4
4247CS–SCR–11/05
AT83C21GC
Pin Description
Figure 2. 24-pin SSOP Pinout
P1.1/CC8
P1.4/CCLK
P1.0/CIO
RST
P1.5/CRST
1
P1.3/CC4
P1.2/CPRES
XTAL1
P3.3/INT1/OE
P3.2/INT0
P3.4/T0
P3.5/CIO1/T1
LI
C V
CC
CVSS V
CC
E V
CC
VSS
P3.0/RxD
P3.1/TxD
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
P3.6/CCLK1/LED0 XTAL2
P3.7/CRST1/LED1
D V
CC
SSOP24
Table 1. Port Signal Description
Port
Signal
Name
Internal
Power
Supply ESD Type Description
P1.0 CIO CV
CC
4 kV I/O
Smart Card Interface Function
Card I/O – Pull-up medium is lower than 20K Ω
P1.1 CC8 CV
CC
4 kV I/O
Smart Card Interface Function
Card contact 8 – Pull-up medium must be less than 20K
Ω
P1.2 CPRES V
CC
4 kV I
Smart Card Interface Function
Card presence
P1.3 CC4 CV
CC
4 kV I/O
Smart Card Interface Function
Card contact 4 – Pull-up medium must be less than 20K
Ω
P1.4 CCLK CV
CC
4 kV O
Smart Card Interface Function
Card clock
P1.5 CRST CV
CC
4 kV O
Smart Card Interface Function
Card reset – Pull-up medium must be less than 20K
Ω
P3.0 RxD EV
CC
I
UART Function
Receive data input
P3.1 TxD EV
CC
O
UART Function
Transmit data output.
P3.2 INT0 DV
CC
I/O
Input/Output Function
P3.2 is a bi-directional I/O port with internal pull-ups.
P3.3 INT1 EV
CC
I/O
Input/Output Function
P3.3 is a bi-directional I/O port with internal pull-ups.
P3.4 EV
CC
I/O
Input/Output Function
P3.4 is a bi-directional I/O port with internal pull-ups.
P3.5 CIO1 DV
CC
I/O
Alternate Card Function
Card I/O: Pull-up medium must be less than 20K