usb to serial convertor

[ipek]

avr solution very cheap
www.vga-avr.narod.ru/AVR910_USB_AVR309_RUS.htm
nokia usb loader cable only 2$
**broken link removed**
happy day

 

[drritchie40]

Anyone know of a USB to 2 Port serial IC (which works at 3.3v)?
The only one i can find close is FT2232D but it only works off a 5v supply
thanks

 

[pisoiu]

Anyone know of a USB to 2 Port serial IC (which works at 3.3v)?
The only one i can find close is FT2232D but it only works off a 5v supply
thanks

The FT2232 as well as other FT chips works at 5V with the USB engine, and those 5V are taken from USB connector. But if you connect VCCIOA and VCCIOB at 3,3v, then the data interfaces will work at 3,3V. I do not see why do you want it to work at 3,3v since you have 5V at the USB connector anyway.

/pisoiu

 

[WVV]

I think, you can use PL2303:
TTL output,
need not program,
quite simple circuit,
about 2$ 1pc.

from its datasheet:


Full compliance with the USB Specification v1.1 and USB CDC v1.1

Support the RS232 Serial interface

Support automatic handshake mode

Support Remote wake-up and power management

256 bytes buffer each for upstream and downstream data flow

Support default ROM or external EEPROM for device configuration

On chip USB transceiver

On chip crystal oscillator running at 12M Hz

Supports Windows 98/SE, ME, 2000, XP, Windows CE3.0, CE .NET, Linux, and Mac OS

28 Pins SOIC package

 

[jshroff]

I think, you can use PL2303:
TTL output,
need not program,
quite simple circuit,
about 2$ 1pc.

Do you know who sells these? Prolific's website does not have any info and mentions speaking with their FAE, I would like to explore this option since the FT232RL solution is a bit more expensive.

 

[WVV]

TO: jshroff
I don't exactly know who sells? But it came into market a long time, it should be easy to buy.

 

[melc]

Anyone know of a USB to 2 Port serial IC (which works at 3.3v)?
The only one i can find close is FT2232D but it only works off a 5v supply
thanks

The FT2232 as well as other FT chips works at 5V with the USB engine, and those 5V are taken from USB connector. But if you connect VCCIOA and VCCIOB at 3,3v, then the data interfaces will work at 3,3V. I do not see why do you want it to work at 3,3v since you have 5V at the USB connector anyway.

/pisoiu

Some applications are requiring 3.3V. Most are based on memory devices. But the FTDI has a solution for this, it's on the datasheet, an external 3.3V regulator.
However FT232BM is quite expensive. On the other hand the USB/RS232 it might work without a complete RS232 interface (Rx. Tx, GND is often enough).

 

[badar shah]

Although the thread is closed for long.
But for people coming now from search the given link might be useful. i didnt test it but it a easy circuit.
USB to Serial Adapter RS-232

 

[electronicsbasecom]

Hello guys,

I think that this text can be usefull here, but originaly is answer for one of topics from this forum.

We work a lot of with microcontrolers and RS232 comunication is a very important. Some devices contain embedded MAX232, others use TTL levels (5V or 3.3V). Because of that we made small PCB with FTDI FT232RL chip for this pourposes. Configuration is made trough jumpers, and board can give extern supply for other devices (USB supplied). Also, we fgured out how to configure FT232RL chip.

You can see shematic and even make your own PCB, just visit link: LINK or https://www.electronics-base.com/in...cts/143-usb-to-serial-adapter-using-ftdi-chip

Greetings...

 

[tpetar]

With few last post you are really surprised HD of server to read some old clasters, by awakening this old thread from dead. :smile:

You can directly use your uC with USB :

V-USB
Virtual USB port for AVR
https://www.obdev.at/products/vusb/index.html

- - - Updated - - -

Also look this example

USB to Serial Converter using ATmega8 /48

Notes: The RxD and TxD must be connect to IC RS233 (IC MAX 232 or other) if want RS 232 sinyal level

https://technosains.com/USBtoSerialConverter.htm