ST STM32F10 Series User Manual

General purpose and alternate function I/O (GPIO and AFIO) UM0306
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5.2 GPIO register description
Refer to Section 1.1 on page 23 for a list of abbreviations used in register descriptions.
5.2.1 Port configuration register low (GPIOx_CRL) (x=A..E)
Address Offset: 00h
Reset value: 4444 4444h
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
CNF7[1:0] MODE7[1:0] CNF6[1:0] MODE6[1:0] CNF5[1:0] MODE5[1:0] CNF4[1:0] MODE4[1:0]
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw
1514131211109876543210
CNF3[1:0] MODE3[1:0] CNF2[1:0] MODE2[1:0] CNF1[1:0] MODE1[1:0] CNF0[1:0] MODE0[1:0]
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw
Bits 31:30, 27:26,
23:22, 19:18,
15:14, 11:10, 7:6,
3:2
CNFx[1:0]: Port x configuration bits (x= 0 .. 7)
These bits are written by software to configure the corresponding I/O port.
Refer to Table 11: Port bit configuration table on page 74.
In input mode (MODE[1:0]=00):
00: Analog input mode
01: Floating input (reset state)
10: Input with pull-up / pull-down
11: Reserved
In output mode (MODE[1:0]
> 00):
00: General purpose output push-pull
01: General purpose output Open-drain
10: Alternate function output Push-pull
11: Alternate function output Open-drain
Bits 29:28, 25:24,
21:20, 17:16,
13:12, 9:8, 5:4, 1:0
MODEx[1:0]: Port x.x mode bits (x= 0 .. 7)
These bits are written by software to configure the corresponding I/O port.
Refer to Table 11: Port bit configuration table on page 74.
00: Input mode (reset state)
01: Output mode, max speed 10 MHz.
10: Output mode, max speed 2 MHz.
11: Output mode, max speed 50 MHz.
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ST STM32F10 Series Specifications

General

Brand	ST
Model	STM32F10 Series
Category	Microcontrollers
Language	English