Stef <[email protected]> wrote:
> In comp.arch.fpga,
> Alex <[email protected]> wrote:

>>> > I have started using Xilinx Spartan3E 1600E Microblaze Development
>>> > Board and want to use its RS232 facility in my project. This board has
>>> > two RS232 connectors but I cannot figure out what UART it uses. I was
>>> > searching for UART chip on the board (I was actually searching for a
>>> > MAXIM chip) and have seen none.
(snip)

>> The FPGA supplies serial output data using LVTTL or LVCMOS
>> levels to the Maxim device, which in turn, converts the
>> logic value to the appropriate RS-232 voltage level. Likewise,
>> the Maxim device converts the RS-232 serial input data to LVTTL
>> levels for the FPGA.
(snip)

> That's because you snipped the last line of Glen's reply:

>>> The RS232 level shift/buffers should be on the board, though.

> The 'Maxim' chip _is_ the level shifter. Should be something like a
> MAX232 (google for that). But it will probably be a low voltage version
> like the MAX3221 or a simular chip from another manufacturer.

I believe it is the same board as the Spartan3E board, but with
a larger, pin compatible, FPGA.

> So the UART is in the FPGA, the level shifter ("Maxim") outside. Isn't
> there a schematic in the user guide?

See UG230.pdf I believe the MAX3232.

He has the microblaze manual, but that doesn't say much about
the rest of the board.

-- glen