23 replies to this topic

[Frankie]

Connect pin 1 on netduino 1 to pin 2 on netduino 2, pin 2 on netduino 1 to pin 1 on netduino 2, and connect the grounds.

On the sender:

  1:          public static void Main()
   2:          {
   3:              SerialPort port = new SerialPort(SerialPorts.COM1,115200);
   4:              OutputPort led = new OutputPort(Pins.ONBOARD_LED, false);
   5:   
   6:              port.Open();
   7:   
   8:              while (true)
   9:              {
  10:                  led.Write(true);
  11:                  port.Write(buff, 0, buff.Length);
  12:                  Thread.Sleep(100);
  13:                  led.Write(false);
  14:                  Thread.Sleep(900);
  15:                  buff = Encoding.UTF8.GetBytes(DateTime.Now.TimeOfDay.ToString());
  16:              }
  17:          }

On the receiver:

  1:          public static void Main()
   2:          {
   3:   
   4:              SerialPort serial = new SerialPort(SerialPorts.COM1, 115200);
   5:              serial.ReadTimeout = 8;
   6:              serial.DataReceived += new SerialDataReceivedEventHandler(serial_DataReceived);
   7:              serial.Open();
   8:              while (true)
   9:              {
  10:   
  11:                  Thread.Sleep(Timeout.Infinite);
  12:              }
  13:   
  14:          }
  15:   
  16:          static void serial_DataReceived(object sender, SerialDataReceivedEventArgs e)
  17:          {
  18:              int bytesReceived = ((SerialPort)sender).BytesToRead;
  19:              byte[] bytes = new byte[bytesReceived];
  20:              ((SerialPort)sender).Read(bytes, 0, bytes.Length);
  21:              string received = new string(System.Text.Encoding.UTF8.GetChars(bytes));
  22:              Debug.Print(received); 
  23:   
  24:          }

for those who are gonna try this good example:
i think florest meant the first and second pin, so use pin 0 and 1.

[skyjumper]

Is it too late to say AYE to SPI slave mode? For what its worth, I think an Arduino, Netduino or anything similar is much more useful if it can act as an I2C or SPI slave device. As someone pointed out, UARTs are a limited and precious resource, while I2C and SPI are much better for collecting data from sensors.

[Jack Chidley]

Aye. Someone more experienced can educate me here. My thought would be to enable communications with Arduinos, either SPI Master/Slave as appropriate. Why? Glad you asked. There are lots of drivers written for Arduino. Sometimes it makes sense to rewrite these drivers for .net, sometimes it might just be easier to use the Arduino to drive the hardware instead. Then you would just need a cheap arduino chip and write a tiny app to handle the comms instead. SPI seems like the right vehicle for this kind of comms. I guess you could use tcp/ip or other networking too but SPI is cheaper, simpler and faster for short distances. Does this make sense? Jack

[Chris Walker]

Hi Jack, Yes, you could certainly use SPI or UART to talk to an Arduino (or other boards) via SPI. Regarding SPI Slave... The reason that SPI Slave is not supported in NETMF is due to the way that SPI generally works. Data is written and read at the same time. But the data that's read usually has to arrive at the master on very specific clock pulses. This requires microsecond timing and NETMF really isn't set up to support that scenario. That said, we're implementing go!bus over SPI...and providing for a go!bus SPI client connection on STM32F2/4-based modules. So perhaps that could be used for inter-board communication as well (basically a really fast UART with error checking and shared pins). Chris