Problem connecting PC to LPC1768 with Wixel


I’m trying to make a connection between my computer and the mbed LPC1768 using a pair of Wixels. But I’m having some problems:

I read the Wixel guide, installed the drivers and Wixel Configuration Utility and I’m using the Tera Term as the terminal to send data from my PC. But It isn’t working: What are the output pins on the Wixel? I’m using the DTR and RTS outputs but It’s always on HIGH state. Is there a simpler way? What is my error?

Another questions:

I want to send some data, but not from the PC. Am I suposed to use the DTR and RTS?

The Wixel’s guide says:

P1_6 TX transmits serial data (0–3.3 V)
P1_7 RX receives serial data (0–3.3 V, not 5 V tolerant)

USB-to-Radio: Serial bytes from the USB virtual COM port get sent to the radio and vice versa.
UART-to-Radio: Serial bytes from the UART’s RX line get sent to the radio and bytes from the radio get sent to the UART’s TX line.

So, if I have one wixel plugged to PC (USB-to-Radio) and one connected to the LPC1768(UART-to-Radio), the UART-to-Radio Wixel’s P1_6 is a input or a output? Because in the Default Pinout, P1_6 (TX) transmits data and the UART-to-Radio says that the TX line receives data.



Hello, Aguiar.

From your questions it sounds like you are using the Wixel’s Wireless Serial app. Could you please confirm that you are using that app?

- Jeremy

Sure! I’m using the Wixel’s Wireless Serial app.

I’ve set:

nDTR_pin = -1;
nRTS_pin = -1;
nDSR_pin = -1;
CD_pin = -1;

DTR_pin = 10;
RTS_pin = 11;
DSR_pin = 12;
CD_pin = 13;

arduino_DTR_pin = 0

So, I’m using a non-inverted logic.

I’m using the Tera Term as terminal program, and I can see the pair of wixels flashing when I hit a key, so I suppose that the pair is communicating. But, when making the connection between P1_6 and P1_7 to, respectively, Pins 13 and 14 of the LPC1768, I don’t read data.

P.S: Using a multimeter, I saw that most of the pins of the wixel connected to the LPC1768 are on HIGH state. I’m really not understanding.

The output pins for the Wixel when using the Wireless Serial app are described in the Wireless Serial app section of the User’s Guide. You shouldn’t use DTR and RTS for transmitting serial data but use the TX and RX pins.

It looks like you have the Wixel’s transmit pin (TX) going to the TX pin of the mbed. This will not work because both TX pins are outputs. You should connect the TX pin of the Wixel to the RX pin of the mbed. You should connect the RX pin of the Wixel to the TX pin of the mbed.

- Jeremy

Thanks,sir! It solved my problem!