Serial port

[bullt]

hi,
I need to connect on con1 .. 3, a serial device that operates at a voltage of 3.3v. But the feeding of these connectors is 5v. It would be possible to catch the feeding of 3.3v from elsewhere but using communication signals of this connector?
Thank you.

[nicolas]

What kind of device are you interfacing, some mcu's tolerate 5v on the 3.3v ttl lines.

Otherwise, look into a ttl level converter chip.
Maxim sells these.

[bullt]

It is a "C328-7640 (OV7640) JPEG Compression VGA Camera Module (standard lens holder)

"" Http://www.electronics123.net/amazon/da ... 8-7640.pdf "
The serial port "TXD0 and RXD0" works at 3.3v?

[nicolas]

I dont know. The datasheet doesnt list a maximum voltage on the pins, only the high/low requirements.

[bullt]

The voltage on pins TXD0 and RXD0 of what is?
The MAX3232 uses a Mini2440 to convert the RS232 serial port 0, which is powered to 3.3 v. I guess the serial port voltage of 3.3 v.
Could use TXD0 and RXD0 to communicate with the module, but would have to cojer a supply of 3.3 V, instead of the 5v connector.
What do you think.
Thank you.

[nicolas]

Right, your datasheet doesnt list the max voltage for the TXD/RXD lines of the camera.

On the Mini2440
Uart0 as it comes out is NOT 5v. It is +-12v due to the MAX232 chip.
I recommend you use Uart1/2 as these are 5v, directly interfaceable with a MCU or similar.