芯片的Active low 是啥意思

Active low 是指当信号线为低电平(通常为0V)时，信号被认为是有效的。Active low 的信号线通常在高电平时处于非活动状态，只有在低电平时才会触发相应的操作。例如，一个悬空的输入引脚可能会被认为是低电平，因为它没有被连接到高电平的电源或信号源。在数字电路中，Active low 信号通常用于控制电路的状态转换或启动某个操作。

相关问题

写一个ADS1118芯片驱动代码

以下是一个基本的ADS1118芯片驱动代码，使用SPI总线进行通信：

#include <SPI.h>

#define CS_PIN 10 // Chip select pin
#define DRDY_PIN 6 // Data ready pin

// ADS1118 register addresses
#define REG_CONVERSION 0x00
#define REG_CONFIG 0x01

// Configuration register bit fields
#define CFG_OS_BIT 15
#define CFG_MUX_BIT 12
#define CFG_PGA_BIT 9
#define CFG_MODE_BIT 8
#define CFG_DR_BIT 5
#define CFG_COMP_MODE_BIT 4
#define CFG_COMP_POL_BIT 3
#define CFG_COMP_LAT_BIT 2
#define CFG_COMP_QUE_BIT1 1
#define CFG_COMP_QUE_BIT0 0

// Configuration register values
#define CFG_OS_SINGLE_CONV 0x8000 // Start single conversion
#define CFG_MUX_AIN0_AIN1 0x0000 // Differential inputs AIN0 and AIN1
#define CFG_PGA_6_144V 0x0000 // Full scale range +/-6.144V
#define CFG_MODE_SINGLE_CONV 0x0100 // Single conversion mode
#define CFG_DR_128SPS 0x0000 // Data rate 128 samples per second
#define CFG_COMP_MODE_TRADITIONAL 0x0000 // Traditional window comparator mode
#define CFG_COMP_POL_ACTIVE_LOW 0x0000 // Active low comparator polarity
#define CFG_COMP_LAT_NON_LATCHING 0x0000 // Non-latching comparator
#define CFG_COMP_QUE_ASSERT_AFTER_1_CONV 0x0000 // Assert after one conversion

void setup() {
  // Initialize SPI communication
  SPI.begin();
  SPI.setDataMode(SPI_MODE1);
  SPI.setClockDivider(SPI_CLOCK_DIV16);
  
  pinMode(CS_PIN, OUTPUT);
  digitalWrite(CS_PIN, HIGH); // Set chip select pin to high
  
  pinMode(DRDY_PIN, INPUT_PULLUP); // Data ready pin
  
  // Configure ADS1118
  writeRegister(REG_CONFIG, CFG_OS_SINGLE_CONV | CFG_MUX_AIN0_AIN1 | CFG_PGA_6_144V | CFG_MODE_SINGLE_CONV | CFG_DR_128SPS | CFG_COMP_MODE_TRADITIONAL | CFG_COMP_POL_ACTIVE_LOW | CFG_COMP_LAT_NON_LATCHING | CFG_COMP_QUE_ASSERT_AFTER_1_CONV);
}

void loop() {
  // Wait for data ready pin to go low
  while(digitalRead(DRDY_PIN));
  
  // Read conversion value
  int16_t value = readRegister(REG_CONVERSION);
  
  // Do something with the conversion value
}

void writeRegister(uint8_t address, uint16_t value) {
  // Send command byte
  digitalWrite(CS_PIN, LOW);
  SPI.transfer(address);
  
  // Write register value
  SPI.transfer16(value);
  
  digitalWrite(CS_PIN, HIGH);
}

int16_t readRegister(uint8_t address) {
  // Send command byte
  digitalWrite(CS_PIN, LOW);
  SPI.transfer(address);
  
  // Read register value
  int16_t value = SPI.transfer16(0);
  
  digitalWrite(CS_PIN, HIGH);
  
  return value;
}

注意，这只是一个基本的示例代码，实际应用中还需要进行更多的配置和错误处理。

k3588s 平台配置 AP6275 芯片，蓝牙配置DTS文件

好的，以下是一个可能的 AP6275 蓝牙配置的 DTS 文件示例：

&uart9 {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_uart9>;
    status = "okay";
};

&spi2 {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_spi2>;
    cs-gpios = <&gpio1 1 GPIO_ACTIVE_LOW>;
    status = "okay";
};

&hci_uart {
    status = "okay";
    btreg-on-gpios = <&gpio1 2 GPIO_ACTIVE_LOW>;
    btreg-reset-gpios = <&gpio1 3 GPIO_ACTIVE_LOW>;
    wakeup-gpios = <&gpio1 4 GPIO_ACTIVE_LOW>;
    firmware-name = "ap6275/fw_bcm43438a0.bin";
    firmware-name-sdio = "ap6275/fw_bcm43438a0.bin";
    firmware-name-sdio-s3 = "ap6275/fw_bcm43438a0.bin";
    firmware-name-sdio-s4 = "ap6275/fw_bcm43438a0.bin";
    firmware-name-sdio-s5 = "ap6275/fw_bcm43438a0.bin";
    firmware-name-sdio-s6 = "ap6275/fw_bcm43438a0.bin";
    firmware-name-sdio-s7 = "ap6275/fw_bcm43438a0.bin";
    firmware-name-sdio-s8 = "ap6275/fw_bcm43438a0.bin";
    firmware-name-sdio-s9 = "ap6275/fw_bcm43438a0.bin";
    firmware-name-sdio-s10 = "ap6275/fw_bcm43438a0.bin";
    firmware-name-sdio-s11 = "ap6275/fw_bcm43438a0.bin";
    firmware-name-sdio-s12 = "ap6275/fw_bcm43438a0.bin";
    firmware-name-sdio-s13 = "ap6275/fw_bcm43438a0.bin";
    firmware-name-sdio-s14 = "ap6275/fw_bcm43438a0.bin";
};

请根据实际硬件连接和需要进行相应的修改，例如更改 UART 和 SPI 的引脚配置，以及修改固件文件名等。同时，也需要确保设备树已正确加载并应用了该配置。