SM39A16M1
8-Bit Micro-controller
16KB with ISP Flash
& 1K+256B RAM embedded
5. GPIO
The SM39A16M1 has four I/O ports: Port 0, Port 1, Port 2, Port 3. Ports 0, 1, 2 are are 8-bit ports and Ports 2, 3 are
are 7-bit ports. These are: quasi-bidirectional (standard 8051 port outputs), push-pull, open drain, and input-only. Two
configuration registers for each port select the output type for each port pin. All I/O port pins on the SM39A16M1 may
be configured by software to one fo four types on a pin-by-pin basis, shown as below:
Mnemonic
Description
Direct
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
RESET
I/O port function register
Port 0 output
mode 0
Port 0 output
mode 1
Port 1 output
mode 0
Port 1 output
mode 1
Port 2 output
mode 0
Port 2 output
mode 1
Port 3 output
mode 0
Port 3 output
mode 1
P0M0
P0M1
P1M0
P1M1
P2M0
P2M1
P3M0
P3M1
D2h
D3h
D4h
D5h
D6h
D7h
DAh
DBh
P0M0 [7:0]
~OP18
00H
00H
00H
00H
00H
00H
00H
P0M1[7:0]
P1M0[7:0]
P1M1[7:0]
-
-
-
-
P2M0[6:0]
P2M1[6:0]
P3M0[6:0]
P3M1[6:0]
*OP18 by writer programming set.
PxM1.y
PxM0.y
Port output mode
0
0
1
1
0
1
0
1
Quasi-bidirectional (standard 8051 port outputs) (pull-up)
Push-pull
Input only (high-impedance)
Open drain
The RESET Pin can define as General I/O P3.4 when user use Internal RESET.
The XTAL2 and XTAL1 can define as P3.5 and P3.6 by writer or ISP，when user use internal OSC as system clock；
when user use external OSC as system clock and input into XTAL1，Only XTAL2 can be defined as P3.5.
For general-purpose applications, every pin can be assigned to either high or low independently As shown below:
Mnemonic
Description
Dir.
Bit 7
Bit 6
Bit 5
Ports
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
RST
Port 3
Port 2
Port 1
Port 0
Port 3
Port 2
Port 1
Port 0
B0h
A0h
90h
80h
-
-
P3.6
P2.6
P1.6
P0.6
P3.5
P2.5
P1.5
P0.5
P3.4
P2.4
P1.4
P0.4
P3.3
P2.3
P1.3
P0.3
P3.2
P2.2
P1.2
P0.2
P3.1
P2.1
P1.1
P0.1
P3.0
P2.0
P1.0
P0.0
7Fh
7Fh
FFh
P1.7
P0.7
~OP19
*OP19 by writer programming set.
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M069 Ver C SM39A16M1 7/31/2013
- 30 -
SYNCMOS [ SYNCMOS TECHNOLOGIES,INC ]
