void main(void) { while(1) { HC595SendData(0xff,0xff,0,0); //清屏 keyNum=Key_Scan(); //读取键值 switch (keyNum) { case(0xFE) : //返回按键K1的数据 translation();//文字从上到下平移 break; case(0xFD) : //返回按键K2的数据 twinkle1(); //文字闪烁 break; case(0xFB) : //返回按键K3的数据 twinkle2(); //符号闪烁 break; // case(0xF7) : //返回按键K4的数据 // ; // break; // case(0xEF) : //返回按键K5的数据 // ; // break; // case(0xDF) : //返回按键K6的数据 // ; // break; // case(0xBF) : //返回按键K7的数据 // ; // break; case(0x7F) : //返回按键K8的数据 HC595SendData(0xff,0xff,0,0); //清屏 break; default: break; } } }

这段代码是一个死循环，主要是用来处理矩阵键盘的输入，并根据不同的按键值执行相应的操作。

具体来说，while循环会一直执行，不断地读取矩阵键盘的输入。先通过 HC595SendData 函数清屏，然后通过 Key_Scan 函数读取键值。接下来使用 switch case 语句，根据不同的键值执行相应的操作。这里的操作包括文字从上到下平移、文字闪烁、符号闪烁以及清屏。如果读取的键值不在以上的 case 中，则不执行任何操作。

需要注意的是，这里只处理了部分键值的情况，其他键值的处理被注释掉了。如果需要增加其他键值的处理，可以取消注释相应的代码，并根据具体需求编写相应的函数。

相关问题

hc595控制点阵屏显示 主函数的循环代码

以下是一个基于HC595控制点阵屏显示的主函数循环代码示例：

#include <reg52.h>

// 定义HC595芯片控制端口
sbit HC595_SCK = P2^0; // 时钟信号
sbit HC595_RCK = P2^1; // 存储信号
sbit HC595_SDI = P2^2; // 数据信号

// 定义点阵屏显示数据
unsigned char displayData[] = {
    0x7F, 0x81, 0x81, 0x81, 0x7F, // 字母A
    0xFF, 0x89, 0x89, 0x89, 0x76, // 字母B
    // ...
};

// 向HC595芯片发送一个字节的数据
void HC595_SendByte(unsigned char byteData) {
    unsigned char i;
    for (i = 0; i < 8; i++) {
        HC595_SDI = (byteData & 0x80) >> 7;
        byteData <<= 1;
        HC595_SCK = 1;
        HC595_SCK = 0;
    }
}

// 向点阵屏显示一个字符
void DisplayChar(unsigned char charIndex) {
    HC595_SendByte(displayData[charIndex]);
    HC595_RCK = 1;
    HC595_RCK = 0;
}

// 主函数
void main() {
    unsigned char i;
    while (1) {
        for (i = 0; i < sizeof(displayData)/sizeof(displayData[0]); i++) {
            DisplayChar(i);
            // 控制点阵屏显示的时间
            // ...
        }
    }
}

注：以上代码只是一个示例，具体实现需要根据实际情况进行调整。

74hc595 spi

### 74HC595 SPI Communication Example

The 74HC595 shift register can be effectively interfaced with a microcontroller using the SPI protocol to extend digital outputs. The following sections provide an overview and code examples for implementing this interface.

#### Hardware Setup
To connect the 74HC595 to a microcontroller via SPI, three primary connections are required:

- **Serial Data Input (DS/SDI)**: Connects to MOSI pin on the SPI master.
- **Shift Register Clock (SH_CP/SCK)**: Connects to SCLK pin on the SPI master.
- **Storage Register Clock (ST_CP/LATCH)**: This line is typically controlled separately as it does not directly correspond to standard SPI signals but acts similarly to CS/SS in functionality by latching data into output registers after shifting.

Additionally, ensure that all devices share common ground references.

#### Software Implementation
Below is a simple implementation demonstrating how to send data from an STM32 MCU over SPI to control multiple LEDs connected through one or more cascaded 74HC595 chips.

#include "stm32f4xx_hal.h"

// Define GPIO pins used for Latch signal
#define LATCH_PORT    GPIOA
#define LATCH_PIN     GPIO_PIN_8

void HAL_SPI_MspInit(SPI_HandleTypeDef *hspi){
    /* Enable clocks */
    __HAL_RCC_GPIOB_CLK_ENABLE();
    __HAL_RCC_SPI1_CLK_ENABLE();

    // Configure SPI1 pins: SCK, MISO, MOSI
    GPIO_InitTypeDef gpio_init;
    
    gpio_init.Pin       = GPIO_PIN_3 | GPIO_PIN_4 | GPIO_PIN_5;  
    gpio_init.Mode      = GPIO_MODE_AF_PP;
    gpio_init.Pull      = GPIO_NOPULL;
    gpio_init.Speed     = GPIO_SPEED_FREQ_VERY_HIGH;
    gpio_init.Alternate = GPIO_AF5_SPI1;

    HAL_GPIO_Init(GPIOB,&gpio_init);

    // Initialize LATCH Pin
    gpio_init.Pin   = LATCH_PIN;
    gpio_init.Mode  = GPIO_MODE_OUTPUT_PP;
    gpio_init.Pull  = GPIO_NOPULL;
    gpio_init.Speed = GPIO_SPEED_FREQ_LOW;
    HAL_GPIO_Init(LATCH_PORT,&gpio_init);
}

uint8_t spi_data[] = {0xFF}; // All LED ON pattern

int main(void){
    HAL_Init();
    SystemClock_Config(); 

    SPI_HandleTypeDef hspi1;
    hspi1.Instance               = SPI1;
    hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_2;
    hspi1.Init.Direction         = SPI_DIRECTION_2LINES;
    hspi1.Init.CLKPolarity       = SPI_POLARITY_LOW;
    hspi1.Init.CLKPhase          = SPI_PHASE_1EDGE;
    hspi1.Init.DataSize          = SPI_DATASIZE_8BIT;
    hspi1.Init.FirstBit          = SPI_FIRSTBIT_MSB;
    hspi1.Init.TIMode            = SPI_TIMODE_DISABLE;
    hspi1.Init.CRCCalculation    = SPI_CRCCALCULATION_DISABLE;
    hspi1.Init.NSS               = SPI_NSS_SOFT;
    if(HAL_SPI_Init(&hspi1)!= HAL_OK){
        Error_Handler();
    }

    while(1){
        // Toggle latch low-high to transfer shifted bits into storage register
        HAL_GPIO_WritePin(LATCH_PORT,LATCH_PIN,GPIO_PIN_RESET); 
        HAL_Delay(1);
        
        // Send byte(s) containing desired state of each bit/output
        HAL_SPI_Transmit(&hspi1,(uint8_t*)spi_data,sizeof(spi_data),HAL_MAX_DELAY);
        
        HAL_GPIO_WritePin(LATCH_PORT,LATCH_PIN,GPIO_PIN_SET);
        HAL_Delay(1000); // Delay between updates
    }
}

This program initializes SPI peripheral settings suitable for communicating at higher speeds without compromising stability[^4]. After setting up hardware parameters like clock polarity and phase according to datasheet specifications, sending commands becomes straightforward using `HAL_SPI_Transmit()` function calls within loops where necessary changes occur periodically.