-7-
Pin No.
Pin Name
I/O
Description
IC DESCRIPTION -1/1 (AN2136SC) -1/2
1
2
3 ~ 6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
GND
CLK24
GND
AGND
XIN
XOUT
AVCC
VCC
GND
RESET
PC0/RXD0
PC1/TXD0
____
PC2/INT0
____
PC3/INT1
PC4/T0
PC5/T1
___
PC6/WR
___
PC7/RD
VCC
GND
–
O
–
–
I
O
I
I
–
I
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I
–
Ground
24 MHz clock, phase locked to the 12 MHz input clock.
Ground
Analog ground. Connect to ground with as short a path as possible.
Connect this signal to a 12 MHz series resonant, fundamental mode crystal and 22-33 pF
capacitor to GND.
Analog VCC. This signal provides power to the analog circuit.
3.3V power source
Ground
Active high reset.
Multiplexed pin whose function is selected by the “RXD0” bit of the PORTCCFG register. If
RXD0=0, the pin is the bi-directional I/O port bit PC0. If RXD0 = 1 the pin is the active-high
RXD0 from 8051 UART0, which provides data to the UART in all modes.
Multiplexed pin whose function is selected by the “TXD0” bit of the PORTCCFG register. If
TXD0=0, the pin is the bi-directional I/O port bit PC1. If TXD0 = 1 the pin is the active-high
TXD0 signal for 8051 UART0, which provides the output clcok in sync mode, and the output
data in async mode.
Multiplexed pin whose function is selected by the “INT0” bit of the PORTCCFG register. If
INT0=0, the pin is the bi-directional I/O port bit PC2. If INT0 = 1 the pin is the active-low 8051
INT0 interrupt input signal, which is either edge triggered (IT0=1) or level triggered (IT0=0).
Multiplexed pin whose function is selected by the “INT1” bit of the PORTCCFG register. If
INT1=0, the pin is the bi-directional I/O port bit PC3. If INT1 = 1 the pin is the active-low 8051
INT1 interrupt input signal, which is either edge triggered (IT1=1) or level triggered (IT1=0).
Multiplexed pin whose function is selected by the “T0” bit of the PORTCCFG register. If T0=0,
the pin is the bi-directional I/O port bit PC4. If T0 = 1 the pin is the active-high T0 signal for
8051 Timer 0, which provides the input to Timer 0 when C/T0 is 1. When C/T0 is 0, Timer0
does not use this bit.
Multiplexed pin whose function is selected by the “T1” bit of the PORTCCFG register. If T1=0,
the pin is the bi-directional I/O port bit PC5. If T1 = 1 the pin is the active-high T1 signal from
8051 Timer 1, which provides the input to Timer 1 when C/T1 is 1. When C/T0 is 0, Timer1
does not use this bit.
Multiplexed pin whose function is selected by the “WR” bit of the PORTCCFG register. If
WR=0, the pin is the bi-directional I/O port bit PC6. If WR = 1 the pin is the active-low write
signal for external memory.
Multiplexed pin whose function is selected by the “RD” bit of the PORTCCFG register. If
RD=0, the pin is the bi-directional I/O port bit PC7. If RD = 1 the pin is the active-low read
signal for external memory.
3.3V power source
Ground
