FullDuplexSerial

Sabre00

I have an application where I send data to an LCD screen and if the user desires can communicate with the device if they connect it to a PC. I Would like to send out the data via the serial port even if the serial cable is connected or not. I am using the PropStick USB and I am using the download pins to communicate with the PC through the same USB serial port. I use hyperterminal to communicate with the device.

The device responded as it should when I have the USB mini port in and connected to the USB is connected to the PC, even if hyperterminal is on or not.

However when I disconnect the device from the computer when the device comes to the code where the device has to send the data serially it seems to stall and resets itself.

I see that the FullDuplexSerial object uses a 16 byte txbuffer and rxbuffer. There is a rxflush but there doesn't seem to be a txflush.

could it be that the device might be stalling because it does not "see" that a serial device is not connected? or is it that the txbuffer needs flushing?

william chan

txbuffer does not need flushing because there is no flow control.
The Prop does not try to detect whether there is anything there or not.
It send sends whatever that needs to be transmitted.

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Sabre00

so therefore my resetting issues aren't related to my serial sending.... will have a look at my code again and see if it is something in there.

dMajo

Search the forum, there is a complete topic discussing reset issues due to unpowered FTDI usb to serial converter (the IC is powered via usb)