GPIOB->CRH&=0XFFFFFF0F;GPIOB->CRH|=8<<12;怎么配置

GPIOB->CRH refers to the configuration register high of the GPIOB port. It is a 32-bit register that is used to configure the behavior of the pins of the GPIOB port. Each pin of the port has 4 bits in this register which are used to configure the pin mode, output type, speed, and pull-up/pull-down resistors.

The CRH register is used for the pins 8 to 15 of the GPIOB port, while the CRL register is used for the pins 0 to 7. The configuration of the pins can be set using bitwise operations and constants defined in the STM32F103xx.h header file.

For example, to set pin 12 of GPIOB as an output pin with a maximum output speed of 50 MHz, the following code can be used:

GPIOB->CRH |= GPIO_CRH_MODE12; // Set pin 12 as output
GPIOB->CRH |= GPIO_CRH_CNF12_1; // Set pin 12 as push-pull output
GPIOB->CRH |= GPIO_CRH_MODE12_1; // Set pin 12 to maximum output speed of 50 MHz

Note that this code assumes that the GPIOB clock has already been enabled and that the appropriate pins have been configured as GPIO pins using the GPIOB->CRL register.