Rainbow Electronics AT89C5122 - Manual (Page 58)

58
AT8xC5122/23
4202E–SCR–06/06
The “Port51” is described in Figure 24.
Figure 24. Quasi Bi-directional Port
Push-pull Output
Configuration The push-pull output configuration has the same pull-down structure as both the open
drain and the quasi-bi-directional output modes, but provides a continuous strong pull-
up when the port latch contains a logic 1. The push-pull mode may be used when more
source current is needed from a port output.
The Push-pull port configuration is shown in Figure 25.
Figure 25. Push-pull Output
Input with Medium or Weak
Pull-up Configuration The input with pull-up (Input MPU and Input WPU) configuration is shown in Figure 26.
2 CPU
Input
Pin
Strong Weak Medium
N
P P P
CLOCK DELAY
Port Latch
Data
Data
DPU (AUXR.7)
Vss
vcc vcc vcc
Pin
Strong
N
P
Port latch
Data
PMOS
NMOS