usb ttl 232 cable based on prolific pl2303 Moderators: adafruit_support_bill, adafruit

[suhl]

trying to re-purpose an old no-name cable (I think it was originally for communicating with a nokia phone) for programming my arduino, botanicalls kit, etc. similar functionality to the ftdi cable sold at adafruit:

http://www.adafruit.com/index.php?main_ ... ucts_id=70

the cable (usb on one end) has an embedded prolific pl2303 chip (additional markings on the chip read 0412H). the chip sits on a small board that has a few passive components (smt resistors, caps, 12MHz oscillator, etc) and 9 output solder pads, 8 of which are connected.

I've traced the pads back and they connect to the following pl2303 pins (based on the pl2303 datasheet I found here http://user.chollian.net/~mines/pl2303.pdf ):

RXD, TXD, CTS_N, RTS_N, GND, DTR_N, RI_N, DCD_N

my understanding is that I will only need the first 5 of those listed above but I am still missing a VCC.

I plugged in the usb end (showed up in syslog as "vendor 0x067b product 0x2303, rev 1.10/2.02") and measured the voltage relative to ground on each output. all voltages measured were either +3.3V or below.

DTR_N and RTS_N both measure 3.3V and are not needed otherwise - can I use one of those to provide the votage?

thanks!

[adafruit]

you can get 5V directly from the USB connector

[suhl]

ah, perfect, thank you so much. answer was right under my nose of course ;)

[ocon]

Hi...

What is output of PL-2303?
Is that RS232 or TTL?

Could I use it to make USB to TTL interface like FT232 cable?
Do I need e.g Max232 to convert the output level to TTL?

Thanks.

[westfw]

Output of the phone cables is typically TTL or 3.3V logic levels. You can put together a very cheap USB/Arduino sort of converter using one of the cheap imported mass-produced "phone cables":
http://www.uchobby.com/index.php/2009/1 ... /#more-492

[oPossum]

There are several versions of the PL2303 chip. The older versions can be configured for 3.0V to 5.0V and are 5V tolerant. They are usually configured for 5V. The new versions can be configured for 1.8V to 3.3V and are not 5V tolerant. They are usually configured for 3.3V.
The outputs are CMOS levels (rail-to-rail), the inputs have TTL threshold ( < 0.8 low, > 2.0 high).

[Dids]

I'm doing something very similar, same kind of cable with the same PL2303 chip.
Anyone happen to have a picture of the pin outs?
Planning to use the cable with a DC Boarduino, so I don't have to build/buy an inverter/new cable.

[oPossum]

Cables that look like this...


May have this inside...