Go Down

Topic: Make your Arduino USB for only 1 dollar! (Read 14 times) previous topic - next topic

Ian Chilton

Hi,

Quote
The trick to finding DTR/RTS however is to look at the datasheet for the specific Prolific chip used and then check to see if the DTR pin is brought out to some nearby pad. On mine it was not, so the only option left was to solder a tiny wire from the chip pin itself.

The problem is you can't see the chip as it's covered with one of those black blobs - so all you have is the pads on the pcb :(

Ian

BenF

Quote
Any ideas how I can find DTR (and RTS) and why i'm not seeing it?

The cables I've converted don't look quite like yours.

The trick to finding DTR/RTS however is to look at the datasheet for the specific Prolific chip used and then check to see if the DTR pin is brought out to some nearby pad. On mine it was not, so the only option left was to solder a tiny wire from the chip pin itself.

Anachrocomputer

Thanks for posting that detailed tear-down of the USB/serial cable!  I have two like that one, and the information will be very useful.  So far, I've cut the end off one cable, but the other is intact -- not for long!

Ian Chilton

Hi,

I have bought 2 cables, a CA-42 and a DKU-5.

Both arrived and have the PL-2303 chip and when stripped down, both look exactly like this board (and one has the exact same markings):
http://kwartzlab.ca/blog/dw/2010-04-23/reverse-engineering-cheap-ardu

However, for some reason my RXD pin is Pin 4 instead of the 9 in the article which is strange!

Once i'd sorted that though, I can get 5v between GND (6) and VCC (2) and I can connect RXD (4) to TXD (12) and successfully echo characters across in Hyperterm and Realterm.

However, I want to also use DTR so Arduino will auto-reset on program but i'm having trouble finding the DTR pin. I have set DTR and RTS using the toggles in Realterm but going through all the pins with a multimeter between GND (6) and the other pins, none seems to give anything.

Any ideas how I can find DTR (and RTS) and why i'm not seeing it?

The other thing I dont quite understand is why on the above link he uses pin 10, which he had identified as RTS and uses it & calls it DTR in his final pin-out....any ideas why he did that?

Thanks,

Ian

deSilva

Its not a matter of voltage but of current.. nevertheless do what you want  ;D

Go Up