PL2303 driver guide ?

If you are lucky, you *could* get the API from Prolific. FTDI offers a similar service under NDA.

Meindert

Thanks Meindert, May be that API is the exact thing I need now. Can you tell me how to get the PL2303's API ?

Thank you very much, N.L.Trung

When I wrote a driver for this chip, I gleaned the apparently reverse-engineered interface information from the appropriate Linux device driver.

-- Michael N. Moran (h) 770 516 7918

"So often times it happens, that we live our lives in chains and we never even know we have the key." The Eagles, "Already Gone"

The Beatles were wrong: 1 & 1 & 1 is 1

Well, here's what I wrote earlier:

So, contact Prolific...

Meindert

Hi Michael,

Actually I am writting the PL2303 driver base on some reverse-engineere information retrieved by monitoring the data transfer process between PL2303-based USB-RS232 cable and PC. Now I can enumerate the PL2303, se the COM settings like baudrate, stop bits, parity... I can send as man data as I like from the embedded USB host to PL2303 as well. But there i still a big problem because the host cannot get data from PL2303. Now I need some more information on:

1. How to be notified when there's some data in the Receive buffer o PL2303.
2. How to know the amount of data in the Receive buffer of PL2303.

Best, N.L.Trung

You have to poll the PL2303 for that. Remember, USB is a master/slave system where a slave NEVER starts transmitting by itself. Transmission of a slave is always a response to a request from the master.

Meindert

"trungnl" ...

You did read the datasheet and manuals at this site?

Arie de Muynck

Yes I did read all the docs at Prolific Website, but they lack all th information needed to develop PL2303's driver. I think FTDI has a bette product, the FT232BM, but PL2303 is much cheaper so I must choos Prolific's product to reduce overall cost.

Thanks Meindert,

I have implemented a polling mechanism to get data from PL2303 to th embedded host. But there is another problem

According to PL2303's spec, the chip has an 256-byte-buffer for each T and Rx operation. But when I transfer a large amount of data (about 3KB to the RS232 interface of PL2303, the USB host can only read a few byte from the USB interface. It seems that the data in PL2303's buffer has los so I cannot read all the data transfered to RS232 interface.

Without knowing all the details, I'd say: poll more often. You have to at least poll often enough not to let your 256 buffer fill up.

Meindert