CTS RTS handshake clarification

[lmoreau]

Hi,

We have a custom board with LQFP100 chip, the UART COM2  is connected to a  chip modem transmitter system using the power line. 

It seems that the CTS1 input (pin 73) connected to the RTS modem output doesn’t regulate the output. 

Have we missing something ?

Here is the transmitting code

 port = new SerialPort("COM2", 38400, Parity.None, 8, StopBits.One);
 port.Handshake = System.IO.Ports.Handshake.RequestToSend;
 port.Open();

public static void SendSerial(string xmsg)
        {
            byte[] msg = Encoding.UTF8.GetBytes(xmsg);
            try
            {
                port.Write(msg, 0, msg.Length);
            }
            catch
            {
            }
      // Wait loop as CTS line seems not to block transmission
            Thread.Sleep(50);
        }


Regards
Loïc

[SupportAdmin]

We have a custom board with LQFP100 chip

You mean USBizi 100?

Are you using the latest firmware? What is your firmware version?

[support]

When you send data through UART. It will be stored an a FIFO. so Write() is independent from the transmission and it will not block if the the CTS was not asserted. But when you CTS is asserted the ART engine will transmit the bytes.

[lmoreau]

Thanks for your fast reply

To explain a bit further i have attached a dump of the two traces issued from TX and CTS lines, as you can see the TX line doesn't care of the CTS state. To do further tests i will connect CTS to VSS 3.3V to see if the data stream is blocked.

Yes we are using USBizi100 and our firmware is dated on 12/16/2009   with framework 3.0, i know that it is not yet supported but this version seems stable and we are using serialization wich need to be rewrite as v 4.0 doesnt support it. 


regards
Loïc
 

[SupportAdmin]

We no longer suport 3.0 and very soon will be doping 4.0 and moving to 4.1. Sorry I couldn't provide a better answer.

[lmoreau]

Fixed,

We have inverted the RTS signal from our modem connected to USBIzi CTS by removing the mosfet driver and now everything is running fine, the error was originating from our power line modem with a supposed inverted RTS signal.

By the way i would like to know is serialisation is supported in MF 4.1  ?, and if you can confirm that  VS2010 is mandatory .   

regards
Loïc

[GHI_Support]

If you are using 4.1, VS 2010 is mandatory.
USBizi does not support serialization.