speed>4||speed==0
时间: 2023-11-01 10:48:52 浏览: 29
This is a logical expression that evaluates to "true" if the speed is greater than 4 or if the speed is equal to 0. Otherwise, it evaluates to "false".
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GPIOA->CRL|=0X33308300;
这段代码是对 GPIOA 的 CRL 寄存器进行配置,将其设置为特定的值。
具体来说,这段代码将 GPIOA 的前 8 个引脚(即 PA0~PA7)配置为推挽输出模式,输出速度为 50MHz。其中,GPIOA->CRL 的低 4 位对应 PA0,依次类推,因此代码中的 0X33308300 就是将这 8 个引脚的配置信息打包成一个 32 位数值,写入到 GPIOA->CRL 寄存器中。
具体的配置信息如下:
- MODE:推挽输出模式
- CNF:通用推挽输出
- SPEED:输出速度为 50MHz
因此,GPIOA->CRL |= 0X33308300 的含义是将 GPIOA 的前 8 个引脚配置为推挽输出模式,输出速度为 50MHz。
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.
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