Serial communication

[upojzsb]

My computer is Macbook, and I bought a USB-TTL Converter which is based on pl2303. I have installed the device of this driver, and there is a file called /dev/tty.usbserial . I insert the line into the raspberry pi before I give it power, and I run screen /dev/tty.usbserial 115200, and connected the electrical plug, but there is nothing happened, there is nothing be printed in the terminal.
The converter is not damaged, what can i do?I'm using Raspberry Pi 2.
By the way, English is not my mother tongue, so I might do some grammatical error , please understand , thank you.

[asandford]

My computer is Macbook, and I bought a USB-TTL Converter which is based on pl2303. I have installed the device of this driver, and there is a file called /dev/tty.usbserial . I insert the line into the raspberry pi before I give it power, and I run screen /dev/tty.usbserial 115200, and connected the electrical plug, but there is nothing happened, there is nothing be printed in the terminal.
The converter is not damaged, what can i do?I'm using Raspberry Pi 2.
By the way, English is not my mother tongue, so I might do some grammatical error , please understand , thank you.

The Pi is not TTL voltage level tolerant, only 3v3.

[upojzsb]

My computer is Macbook, and I bought a USB-TTL Converter which is based on pl2303. I have installed the device of this driver, and there is a file called /dev/tty.usbserial . I insert the line into the raspberry pi before I give it power, and I run screen /dev/tty.usbserial 115200, and connected the electrical plug, but there is nothing happened, there is nothing be printed in the terminal.
The converter is not damaged, what can i do?I'm using Raspberry Pi 2.
By the way, English is not my mother tongue, so I might do some grammatical error , please understand , thank you.

The Pi is not TTL voltage level tolerant, only 3v3.

I didn't link vcc to my Pi,i only link RXD TXD and GND

[asandford]

I didn't link vcc to my Pi,i only link RXD TXD and GND

The TX lead will still have a high value of 5V going into the (3v3 only) RX pin.

[upojzsb]

I didn't link vcc to my Pi,i only link RXD TXD and GND

The TX lead will still have a high value of 5V going into the (3v3 only) RX pin.

But i can use the same device on my Pi, link to my Pi with the USB-TTL Converter and it really works.

[stderr]

I didn't link vcc to my Pi,i only link RXD TXD and GND

The TX lead will still have a high value of 5V going into the (3v3 only) RX pin.

But i can use the same device on my Pi, link to my Pi with the USB-TTL Converter and it really works.

Even if something that is delivering 5 volts doesn't instantly damage something that is supposed to only see 3.3 volts doesn't mean that you should do it.

I remember when I was about ten and I had this transistor radio that I wanted to hook up to big speakers. The speaker in the radio was much higher impedance than the big speaker. So it was great, this little tiny transistor radio was *loud*. I had such fun with it until the electrolytic capacitors blew up. Then I didn't have a radio any more. Sad.

What I've read about the pi is that the 3v3 parts are not 5v tolerant. Google tells me the same thing. People here are saying that. I would follow the advice to not hit them with more than 3.3 volts. But that's just me, I'm still sad about my poor little transistor radio.