Multiple (4x) SPI device on rasberry pi 2 running windows 10 iot

问题

I had successfully communicate single SPI device (MCP3008). Is that possible running multiple (4x) SPI device on raspberry pi 2 with windows 10 iot?

I'm thinking to manually connect the CS(chip select) line and activate it before calling spi function and in-active it after done the spi function. Can it be work on windows 10 iot?
How about configure the spi chip select pin? Change the pin number during the SPI initialization? Is that possible?
Any smarter way to use multiple (4 x MCP3008 ) SPI device on windows 10 iot?

(I'm planning to monitor 32 Analogue signal which will be input to my raspberry pi 2 running windows 10 iot)

Thanks a lot!

回答1:

From: https://projects.drogon.net/understanding-spi-on-the-raspberry-pi/

The Raspberry Pi only implements master mode at this time and has 2 chip-select pins, so can control 2 SPI devices. (Although some devices have their own sub-addressing scheme so you can put more of them on the same bus)

I've successfully used 2 SPI devices in the DeviceTester project and Breathalyzer project within Jared Bienz's IoT Devices GitHub repo.

Notice, that in each project, the SPI interface descriptor is declared explicitly in the ControllerName property for the ADC and Display used in both of these projects. Detailed information around the Breathalyzer project can be found on my blog.

    // ADC
    // Create the manager
    adcManager = new AdcProviderManager();

    adcManager.Providers.Add(
        new MCP3208()
        {
            ChipSelectLine = 0,
            ControllerName = "SPI1",
        });

    // Get the well-known controller collection back
    adcControllers = await adcManager.GetControllersAsync(); 

    // Create the display
    var disp = new ST7735()
    {
        ChipSelectLine = 0,
        ClockFrequency = 40000000, // Attempt to run at 40 MHz
        ControllerName = "SPI0",
        DataCommandPin = gpioController.OpenPin(12),
        DisplayType = ST7735DisplayType.RRed,
        ResetPin = gpioController.OpenPin(16),

        Orientation = DisplayOrientations.Portrait,
        Width = 128,
        Height = 160,
    };

回答2:

Of course you can use as many as you want (as many GPIO pins). You just have to indicate the device to which you are calling.

First, set the configuration of the SPI for example, using chip select line 0

settings = new SpiConnectionSettings(0); //chip select line 0
settings.ClockFrequency = 1000000;
settings.Mode = SpiMode.Mode0;

String spiDeviceSelector = SpiDevice.GetDeviceSelector();
devices = await DeviceInformation.FindAllAsync(spiDeviceSelector);
_spi1 = await SpiDevice.FromIdAsync(devices[0].Id, settings);

You can not use this pin in further actions! So now you should configure the output ports using GpioPin class, which you will use to indicate the device.

GpioPin_19 = IoController.OpenPin(19);
GpioPin_19.Write(GpioPinValue.High);
GpioPin_19.SetDriveMode(GpioPinDriveMode.Output);

GpioPin_26 = IoController.OpenPin(26);
GpioPin_26.Write(GpioPinValue.High);
GpioPin_26.SetDriveMode(GpioPinDriveMode.Output);

GpioPin_13 = IoController.OpenPin(13);
GpioPin_13.Write(GpioPinValue.High);
GpioPin_13.SetDriveMode(GpioPinDriveMode.Output);

Always before transfer indicate device: (example method)

private byte[] TransferSpi(byte[] writeBuffer, byte ChipNo)
{
    var readBuffer = new byte[writeBuffer.Length];

    if (ChipNo == 1) GpioPin_19.Write(GpioPinValue.Low);
    if (ChipNo == 2) GpioPin_26.Write(GpioPinValue.Low);
    if (ChipNo == 3) GpioPin_13.Write(GpioPinValue.Low);

    _spi1.TransferFullDuplex(writeBuffer, readBuffer);

    if (ChipNo == 1) GpioPin_19.Write(GpioPinValue.High);
    if (ChipNo == 2) GpioPin_26.Write(GpioPinValue.High);
    if (ChipNo == 3) GpioPin_13.Write(GpioPinValue.High);

    return readBuffer;
}

来源：https://stackoverflow.com/questions/35647533/multiple-4x-spi-device-on-rasberry-pi-2-running-windows-10-iot

标签

raspberry-pi2

spi

windows-10-iot-core

windowsiot