2.选择CPOL和CPHA位,定义数据传输和串行时钟间的相位关系(见图91)。
3.配置SPI_CR1寄存器的LSBFIRST位镇宴运定义帧格式。
4.硬件模式下,在祥漏数据帧的全部传输过程中应把NSS脚连接到高电平;在软件模式下,需设置SPI_CR2寄存器的SSM和SSI位为'1'。
5.必御梁须设置MSTR和SPE位(只当NSS脚被连到高电平,这些位才能保持为‘1’)。
在这个配置里,MOSI引脚是数据输出,MISO引脚是数据输入。
当然不可以。一个是异步通信、一个是同步通信,根本不历察唯用动这个歪念头。肢培看看你能提供SPI接口的那个模块能否提供没此UART吧。否则中间需要加个小单片机转换一下……但是这样显得很蠢。你从整个系统的架构看看在哪里处理合适。
针对 树莓派 封装的 UWP应用 类,以下代码未经测试,聊以抛砖引玉:using System
using System.Collections.Generic
using System.Linq
using System.Text
using System.Threading.Tasks
using Windows.Devices.Gpio
using Windows.Storage.Streams
using Windows.Devices.Enumeration
using Windows.Devices.SerialCommunication
using Windows.Devices.I2c
using Windows.Devices.Spi
namespace SlotAgentApp.Services
{
public class DevicesHelper
{
public static void GPIO(int eLevel=0, int ioPortNumber = 5)
{
// 获得系统板载缺省GPIO controller
GpioController gpio = GpioController.GetDefault()
if (gpio == null)
return// 如果系瞎逗手统板载磨嫌无可用GPIO,则返回
// 打开指定的GPIO
using (GpioPin pin = gpio.OpenPin(ioPortNumber))
{
// Latch HIGH value first. This ensures a default value when the pin is set as output
pin.Write(eLevel==0? GpioPinValue.Low: GpioPinValue.High)
// 设置IO为输出方向
pin.SetDriveMode(GpioPinDriveMode.Output)
} //关闭 pin - will revert to its power-on state
}
#region 示例代码
/*
(一)GPIO接口使用
*/
public void GPIO()
{
// Get the default GPIO controller on the system
GpioController gpio = GpioController.GetDefault()
if (gpio == null)
return// GPIO not available on this system
// Open GPIO 5
using (GpioPin pin = gpio.OpenPin(5))
{
// Latch HIGH value first. This ensures a default value when the pin is set as output
pin.Write(GpioPinValue.High)
// Set the IO direction as output
pin.SetDriveMode(GpioPinDriveMode.Output)
} // Close pin - will revert to its power-on state
}
/*
(二)指带 UART接口
Pin 8 - UART0 TX
Pin 10- UART0 RX
下面的例子先是初始化UART0,然后做了一次读 *** 作和一次写 *** 作
*/
public async void Serial()
{
string aqs = SerialDevice.GetDeviceSelector("UART0") /* Find the selector string for the serial device */
var dis = await DeviceInformation.FindAllAsync(aqs) /* Find the serial device with our selector string */
SerialDevice SerialPort = await SerialDevice.FromIdAsync(dis[0].Id) /* Create an serial device with our selected device */
/* Configure serial settings */
SerialPort.WriteTimeout = TimeSpan.FromMilliseconds(1000)
SerialPort.ReadTimeout = TimeSpan.FromMilliseconds(1000)
SerialPort.BaudRate = 9600
SerialPort.Parity = SerialParity.None
SerialPort.StopBits = SerialStopBitCount.One
SerialPort.DataBits = 8
/* Write a string out over serial */
string txBuffer = "Hello Serial"
DataWriter dataWriter = new DataWriter()
dataWriter.WriteString(txBuffer)
uint bytesWritten = await SerialPort.OutputStream.WriteAsync(dataWriter.DetachBuffer())
/* Read data in from the serial port */
const uint maxReadLength = 1024
DataReader dataReader = new DataReader(SerialPort.InputStream)
uint bytesToRead = await dataReader.LoadAsync(maxReadLength)
string rxBuffer = dataReader.ReadString(bytesToRead)
}
/*
使用上面的例子时,需要在Package.appxmanifest 中修改下权限修改如下
<Capabilities>
<DeviceCapability Name="serialcommunication">
<Device Id="any">
<Function Type="name:serialPort" />
</Device>
</DeviceCapability>
</Capabilities>
*/
/*
(三)I2C 总线
Pin 3 - I2C1 SDA
Pin 5 - I2C1 SCL
下面的例子首先初始化I2C1 然后向地址为0x40的I2C设备写数据
*/
public async void I2C()
{
// Get a selector string for bus "I2C1"
string aqs = I2cDevice.GetDeviceSelector("I2C1")
// Find the I2C bus controller with our selector string
var dis = await DeviceInformation.FindAllAsync(aqs)
if (dis.Count == 0)
return// bus not found
// 0x40 is the I2C device address
var settings = new I2cConnectionSettings(0x40)
// Create an I2cDevice with our selected bus controller and I2C settings
using (I2cDevice device = await I2cDevice.FromIdAsync(dis[0].Id, settings))
{
byte[] writeBuf = { 0x01, 0x02, 0x03, 0x04 }
device.Write(writeBuf)
}
}
/*
(四) SPI 总线
Pin 19 - SPI0 MOSI
Pin 21 - SPI0 MISO
Pin 23 - SPI0 SCLK
Pin 24 - SPI0 CS0
Pin 26 - SPI0 CS1
下面的例子向SPI0 做了一次写 *** 作
*/
public async void SPI()
{
// Get a selector string for bus "SPI0"
string aqs = SpiDevice.GetDeviceSelector("SPI0")
// Find the SPI bus controller device with our selector string
var dis = await DeviceInformation.FindAllAsync(aqs)
if (dis.Count == 0)
return// "SPI0" not found on this system
// Use chip select line CS0
var settings = new SpiConnectionSettings(0)
// Create an SpiDevice with our bus controller and SPI settings
using (SpiDevice device = await SpiDevice.FromIdAsync(dis[0].Id, settings))
{
byte[] writeBuf = { 0x01, 0x02, 0x03, 0x04 }
device.Write(writeBuf)
}
}
#endregion
}
}
欢迎分享,转载请注明来源:内存溢出
评论列表(0条)