138
/
838
Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
Figure 7-2 Input float/pull-up/pull-down configuration
Output mode
When I/O port is configured as output mode:
Schmidt trigger input is activated
Weak pull-up and pull-down resistors are disabled.
Output buffer is activated.
◆
Open-drain mode: '0' on the output register activates N-MOS, and the pin outputs low level.
'1' port on the output register make the pin in a high impedance state (P-MOS
is never activated)
◆
Push-pull mode:
'0' on the output register activates N-MOS, and the pin outputs low level.
'1' on the output register activates P-MOS, and the pin outputs high level.
The data appearing on the I/O pin is sampled to the input data register at every APB2 clock cycle..
Read access to the input data register can get I/O status.
The read access to the output data register gets the last written value.
Bit set/clear register
Write
Write/Read
Input data register
Read
Vss
V
DD
I /0 PIN
Input driver
Diode
Schmitt trigger
ON/OFF
Output Driver
Vss
Input float/pull up/pull down
ON
Output data register
ON/OFF