FTDI cables confusion

cable-assembliescablesftdiserialusb

I went to the store and asked for a FTDI cable however, I need a bit of assistance, apparently I didn't properly do my homework before shopping and I ended up with upper pic.

I need an FTDI cable to configure my Xbee modules so I could transmit wireless voice, however, upon double checking after buying it, I found out that the FTDI cable is supposed to have 6 pins not 4, so I'm getting confused. Also the cable I bought does not have a label saying it's the CA 42, so I end up with two questions that I haven't been able to answer using Google:

Which is the standard FTDI cable, 4 or 6 pin?
Could I still use the 4 pin cable to configure my Xbees?
I opened the plastic case to see the circuit, I can see the missing RTS CTS pins, however I'm still wondering if I should solder them and use them.

enter image description here

Best Answer

You're going to have to look at the specific XBee. An FTDI cable is just typically an adapter that can mate a USB connection to a UART breakout. The absolute minimum for a UART is a +V, GND, TX and RX line (looks like that's what you have). Something like an Arduino will also need a DTR and a CTS line (the other 2 of the 6 you're looking at). The CTS isn't necessarily used, but the DTR line is typically used to trigger a reset for programming.

FTDI is actually a company that makes the USB chip. SparkFun has a number of these, and they call them FTDI adapters (not sure if they started the naming), which is where I've seen them before.

If you're using this just for communication, either should work fine.

NOTE make sure the voltage is correct. That looks like it breaks out a +5V line. If your xbee needs 3.3V, you're going to release all of the magic smoke.

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It sounds like you've connected TX and RX together.

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You can definitely transmit data using just TX & GND.

Firstly, you want to hook up the ATtiny85 TX line to the FTDI RX line (yellow on the TTL-232R). Make sure that the USB adapter can handle 5V - I'm fairly sure even the 3.3V TTL-232R is 5V tolerant.

According to the example page for SoftwareSerial, you need to set the direction of the TX & RX lines in your setup function:

// include the SoftwareSerial library so you can use its functions:
#include <SoftwareSerial.h>

#define rxPin 2
#define txPin 3
#define ledPin 13

// set up a new serial port
SoftwareSerial mySerial =  SoftwareSerial(rxPin, txPin);
byte pinState = 0;

void setup()  {
  // define pin modes for tx, rx, led pins:
  pinMode(rxPin, INPUT);
  pinMode(txPin, OUTPUT);
  pinMode(ledPin, OUTPUT);
  // set the data rate for the SoftwareSerial port
  mySerial.begin(9600);
}

The baudrate will be 4800 in your case. The SoftwareSerial library doesn't seem to support CTS & RTS, so just make sure you aren't using them on the host software.

Check out the reference page for more details, where they talk about some potential timing issues which may be exacerbated if you're running at 1MHz using the internal oscillator on the tiny.

Best Answer

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