mg82fel308 Megawin Technology, mg82fel308 Datasheet - Page 27

• Manufacturer Part Number: mg82fel308
• Description: A Single-chip Microcontroller Based On A High Performance 1-t Architecture 80c51
• Manufacturer: Megawin Technology

Figure 10-3 Input-Only
10.1.4. Open-Drain Output Structure
The open-drain output configuration turns off all pull-ups and only drives the pull-down transistor of the port pin
when the port register contains a logic “0”. To use this configuration in application, a port pin must have an
external pull-up, typically a resistor tied to VDD. The pull-down for this mode is the same as for the
quasi-bidirectional mode. In addition, the input path of the port pin in this configuration is also the same as
quasi-bidirectional mode.
The open-drain port configuration is shown in Figure 10-4.
Figure 10-4 Open-Drain Output
10.2. I/O Port Register
All I/O port pins on the MG82FE(L)308/316 may be individually and independently configured by software to one
of four types on a bit-by-bit basis, as shown in Table 10-2. Two mode registers for each port select the output
type for each port pin.
Table 10-2 Port Configuration Settings
Where x=0~4 (port number), and y=0~7 (port pin). The registers PxM0 and PxM1 are listed in each port
description.
This document information is the intellectual property of Megawin Technology.
© Megawin Technology Co., Ltd. 2009 All rights reserved.
QP-7300-03D
27/84
PxM0.y
Port latch data
Input data
0
0
1
1
Input data
MEGAWIN
MAKE YOU WIN
PxM1.y
0
1
0
1
Port Mode
Quasi-Bidirectional
Push-Pull Output
Input Only (High Impedance Input)
Open-Drain Output
Port
Pin
Port
Pin
MG82FE(L)308/316
Preliminary, v 0.04