136
/
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 7-1 Basic structure of I/O port
I/O function description
7.2.1
I/O mode configuration
I/O mode control is set by configuration registers GPIOx_PL_CFG, GPIOx_PH_CFG and output register
GPIOx_POD(x=A,B,C,D,E,F,G). The I/O configurations in different operation modes are shown in the following
table:
Table 7-1 I/O mode and configuration relationship
Configuration mode
PCFG1
PCFG0
PMODE1
PMODE0
PODx register
Universal
output
Push-Pull
0
0
01: 10MHz max
10: 2MHz max
1: 50MHz max
0 or 1
Open-Drain
1
0 or 1
Alternate
function
output
Push-Pull
1
0
Not use
Open-Drain
1
Not use
Input
Analog mode
0
0
00: reserved
Not use
Input floating
1
Not use
Input pull-down
1
0
0
Input pull-up
1
I/O characteristics under different configurations are shown in the following table: