> Thanks for all the advice. I have a Xilinx spartan 3 starter kit that
> i'd like to use to implement this, but not EDK. Any suggestions for a
> simple CPU to use on the FPGA?
Actually, I think I would give a try to doing it as a state machine
before I tackled the complexity of adding a CPU with memory and IO then
trying to get a program written, compiled or assembled, loaded into the
memory and finding a way to debug the whole thing. If you had a
working CPU with toolset that was fully integrated, that would be
different. But the sequence you are parsing should be pretty simple to
do in a FSM (finite state machine).
What you do to update the display, that is a different matter. But
then that might not be easy in software either. What is your display
task like?
Reply by Jim Granville●February 8, 20062006-02-08
al99999 wrote:
>>PicoBlaze should handle it if it's not too complex. You may run out
>>of instruction space (the 8-bit PicoBlaze for Spartan 3 is limited to
>>1K instructions if memory serves me right). This does not require
>>the EDK and is published as a reference design with source.
>>
>
>
> Is there a C compiler for PicoBlaze?
:) - No, not at that code size / core resource ....
These are tiny cores, intended for simple SW assisting tasks..
There are assemblers, and the AS MacroAssembler now supports both the
Xilinx PicoBlaze, and the open source Lattice Mico8.
See
http://john.ccac.rwth-aachen.de:8000/as/download.html
-jg
Reply by al99999●February 8, 20062006-02-08
>
> PicoBlaze should handle it if it's not too complex. You may run out
> of instruction space (the 8-bit PicoBlaze for Spartan 3 is limited to
> 1K instructions if memory serves me right). This does not require
> the EDK and is published as a reference design with source.
>
Is there a C compiler for PicoBlaze?
Reply by Gabor●February 8, 20062006-02-08
al99999 wrote:
> Thanks for all the advice. I have a Xilinx spartan 3 starter kit that
> i'd like to use to implement this, but not EDK. Any suggestions for a
> simple CPU to use on the FPGA?
>
> Thanks
PicoBlaze should handle it if it's not too complex. You may run out
of instruction space (the 8-bit PicoBlaze for Spartan 3 is limited to
1K instructions if memory serves me right). This does not require
the EDK and is published as a reference design with source.
Regards,
Gabor
Reply by al99999●February 8, 20062006-02-08
Thanks for all the advice. I have a Xilinx spartan 3 starter kit that
i'd like to use to implement this, but not EDK. Any suggestions for a
simple CPU to use on the FPGA?
Thanks
Reply by ●February 7, 20062006-02-07
al99999 wrote:
> Hi,
>
> Has anybody ever designed anything to decode and display GPS NMEA data
> coming out in ascii form from a UART?
>
> Any ideas of where to start or how to go about decoding comma delimted
> ascii strings?
>
> Thanks,
>
> Al
NiosII/e CPU, UART, a very small memory for your code, and you're
nearly done - just write some C code that parses the sentences... as I
remember the NMEA format should be easy enough where you can look for
the starting sequence pretty easily to "sync" the CPU; no need for even
a timer peripheral.
If you're comfortable with C coding I'd say this is an afternoon
project; a more in RTL.
Jesse Kempa
jkempa -at- altera -dot- com
Reply by Rene Tschaggelar●February 7, 20062006-02-07
al99999 wrote:
> Hi,
>
> Has anybody ever designed anything to decode and display GPS NMEA data
> coming out in ascii form from a UART?
>
> Any ideas of where to start or how to go about decoding comma delimted
> ascii strings?
> Hi,
>
> Has anybody ever designed anything to decode and display GPS NMEA data
> coming out in ascii form from a UART?
>
> Any ideas of where to start or how to go about decoding comma delimted
> ascii strings?
I think this would typically be done using a processor rather than an
FPGA. Even a small, single chip MCU would have enough horsepower to
handle the 4800 bps data rate and control a display. But of course
that depends on the interface to the display. Generating a VGA signal
would take a bit more than sending a serial bit map to a small LCD.
If you really want to do this in an FPGA you would need to construct
state diagrams for the logic that will parse the input stream and
generate binary numbers from the characters. This will take some
significant logic since it involves muliplications. Then you need to
design a circuit that will draw lines in your display based on your
current and last position, again, this can be a lot of logic to figure
out.
I think if I was told to do this in an FPGA, I would construct a CPU in
the FPGA (or use one of the CPUs provided by the FPGA vendors) and find
C code to draw the display. The rest of the work is easy in software.
Reply by al99999●February 5, 20062006-02-05
Hi,
Has anybody ever designed anything to decode and display GPS NMEA data
coming out in ascii form from a UART?
Any ideas of where to start or how to go about decoding comma delimted
ascii strings?
Thanks,
Al