I need a transceiver IC for USART that converts 3v to 5v output and 5v to 3v input

[leoren_tm]

Hi to all.
I have a problem on interfacing my microcontroller(5V) to a device which 3.3Volts only. the IC 74h245 could be use, but i would use 2 of it, and ill just need the the transmit and receive data. any IC suitable for it, in which capable for converiting 3.3V to 5V and same time converting 5V to 3.3V at maximum datarate for serial communication or 9600bps would be use?
and also, i cant drive the micro to 3V, because ill be using LCD and other 5V devices

 

[svhb]

how to convert 5v to 3.3v uart

For the Tx line from the microcontroller, you can just use a voltage divider at these speeds (for example 1kOhm from micro to tranceiver, 2kOhm from tranceiver to ground).

For the Rx signal (tranceiver to microcontroller), there will be possible no problem if the input of the microcontroller is TTL-compatible (VIH = 2V).

 

[leoren_tm]

74h245

ahhh thank you..i was thinking an IC like max232... for a reduce component and also for very reliable system, in which i dont have a data on the chip use on the 3volt device,and for the MCU, im using 8051...

 

[mr_anderson]

3 volt uart to 5 volt micro

To convert from 5 volt to 3.3 volt you can connect two diodes in serial each diode drops 0.7 V so you get ( 5V- 1.4V ) = 3.6 V.
Regards

 

[js]

what is output design rules

see this:
**broken link removed**


Features:
* USB 2.0 compliant Full Speed 12Mbps maximum speed; Suspend
supported
* Xon/Xoff handshaking supported; 300bps to 1Mbps
* UART supports 5-8 bit data, 1-2 Stop bits, odd/even and no parity
* Integrated EEPROM with security lock for Vendor ID, product ID, serial and
release number, power descriptor and product descriptor strings
* On-board 3.3V and 5V available
* Virtual COM port drivers allow operation with existing COM port
applications
* Supports Windows (2000 and above), MAC (OSX-9 and above), Linux (2.4
kernel and above)
* Self powered or USB powered; -40 to +85 deg C temp range

 

[leoren_tm]

5 volt 3.3 volt uart

basically i just need a transceiver IC that would convert 3v to 5v output and 5v to 3v input, use on UART.

 

[ercegovac]

uart outputs

I had similar problem, and i just put resistor on series with Tx, and it is working on 57600

 

[Mike K8LH]

output design in sad

You could use a couple MOSFET's in an open-drain configuration with pull-ups...

 

[pradeepkumar1960]

output of uart of a microcontroller

For the Tx line from the microcontroller, you can just use a voltage divider at these speeds (for example 1kOhm from micro to tranceiver, 2kOhm from tranceiver to ground).

For the Rx signal (tranceiver to microcontroller), there will be possible no problem if the input of the microcontroller is TTL-compatible (VIH = 2V).

iam pradeepkumar. Can u pl help me reg c program for rtx1307 with89c51. thans

 

[flanix]

converting 5v uart to 3.3 v

you can use resistance net