UART configuration problems

Ormund Williams ormundw at
Tue Jan 16 08:13:04 EST 2001

Navin Boppuri wrote:
> Hello Ormund,
> >From your mail, I can make out that you worked on the MAX3100 uart before.
> Can you please tell me how I can do a read from the buffer? I am confused as
> to how to read the buffer without overwriting it with the following data.
> How much delay is the right delay? Please help, I am kinda stuck here.
I have no experience with the 823, my interest in PPC-Linux is for a
future project using the IBM 403GC, I am familiar with the 3100 from
another project.

I had already sent you the following steps for reading the FIFO without
loosing characters, you must read the entire FIFO to clear it.

Here are the steps to take:

        1. Read 16bit data from 3100
        2. Check R (bit 15) to see if there is data in FIFO
        3. If R is set: check Framing Error (bit 10)
           and Parity, if used (bit 8), read the character (bit 0-7)
        4. Do the above 3 three steps till R is clear
        5. Set delay for 60 x baud rate period
           (for 9600bps 8-n-1: 6250 micro seconds)

I am assuming that you are not using the interrupt pin on the 3100.

I see that you have written a driver for SPI can you send me a copy?


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