simple FT232RL serial to USB board...

Community PCB Design
1

Hey guys:

I’m trying to build a simple little serial to USB adapter. I’m having difficulty getting it to work though. After building the board I cannot get the PC to detect the adapter.

Here’s my schematic. Can anybody see where I went wrong?

http://rqxq0a.blu.livefilestore.com/y1p … t232rl.bmp

2

It looks ok, if +5V is coming from the board. The 10megaOhm resistor is somewhat pointless here - either depopulate or replace it with a 0-ohm bridge.

Did you build this from the reference designs in the FTDI datasheet?

3

Does the ftdi drive the serial I/O at TTL or RS232 levels. I was under the impression that it’s TTL so it would need, at the least, inversion. probably easier to stick a max232 or similar on to it.

4

Philba:
Does the ftdi drive the serial I/O at TTL or RS232 levels. I was under the impression that it’s TTL so it would need, at the least, inversion. probably easier to stick a max232 or similar on to it.

CMOS levels, but serial doesn’t imply RS232 (unless thats what the original poster wanted :)).

5

theatrus:

Philba:
Does the ftdi drive the serial I/O at TTL or RS232 levels. I was under the impression that it’s TTL so it would need, at the least, inversion. probably easier to stick a max232 or similar on to it.

CMOS levels, but serial doesn’t imply RS232 (unless thats what the original poster wanted :)).

original poster:
After building the board I cannot get the PC to detect the adapter.

You tell me...
6

FTDI is TTL Serial to PC USB port.

I based the circuit off the arduino schematic. I’m using +5V from the PC’s USB port to power the board.

Thanks.

7

weinerschizel:
FTDI is TTL Serial to PC USB port.

I based the circuit off the arduino schematic. I’m using +5V from the PC’s USB port to power the board.

Thanks.

Through a 10M resistor?