Update Picoblaze Code in Bitstream

Hello,

in my actual design im using a few picoblazes. Now I wonder if it is
possible to update the code in the bitstream without a new
implementation run like it is possible with the microcblaze. I checked
data2bram but it allows only an update of 16 Bit wide Brams, not the
necessary 18 Bit.

Thanks,
  Michael

Michael Dreschmann wrote:
> Hello,
>
> in my actual design im using a few picoblazes. Now I wonder if it is
> possible to update the code in the bitstream without a new
> implementation run like it is possible with the microcblaze. I
checked
> data2bram but it allows only an update of 16 Bit wide Brams, not the
> necessary 18 Bit.
>
> Thanks,
>   Michael

Check out Ken Chapmans reply to this in the PicoBlaze forum:

http://toolbox.xilinx.com/cgi-bin/forum?50@171.5RzZaQ3QgOp.0@.ee8a991

Gabor wrote:
> Michael Dreschmann wrote:
> > Hello,
> >
> > in my actual design im using a few picoblazes. Now I wonder if it
is
> > possible to update the code in the bitstream without a new
> > implementation run like it is possible with the microcblaze. I
> checked
> > data2bram but it allows only an update of 16 Bit wide Brams, not
the
> > necessary 18 Bit.
> >
> > Thanks,
> >   Michael
>
> Check out Ken Chapmans reply to this in the PicoBlaze forum:
>
> http://toolbox.xilinx.com/cgi-bin/forum?50@171.5RzZaQ3QgOp.0@.ee8a991

Darn... the link is broken...

Here's the post:

Ken Chapman - 03:54am Dec 14, 2004 PST (#1 of 1) Reply

A new version of DATA2MEM is in development and will support the update
of the
1024x18 memory used for a KCPSM3 program. I have carried out some
initial tests
last week and it worked for me.

Please contact me directly (ken.chapman@xilinx.com) if you would like
to help
me verify it further.

Thanks to the Xilinx Software Development team for adding support of
BRAM in
this aspect ratio.

Regards,

Ken

Hello,

>> http://toolbox.xilinx.com/cgi-bin/forum?50@171.5RzZaQ3QgOp.0@.ee8a991

>Darn... the link is broken...

Here it works, thanks for your help

Michael

Michael,

As of ISE 7.1 Data2MEM does support 18-bit datawidths.

You need to add a BMM and MEM file to the top level of your ISE project.

The BMM should have syntax to describe the instantiation of the BlockRAM 
you instantiated.  An example BMM file is:

////////////////////////////////////////////////////////////////////////
ADDRESS_SPACE picoblaze1 RAMB18 INDEX_ADDRESSING [0x00000000:0x000003FF]
	BUS_BLOCK
		top/picoblaze1/myram [17:0];
	END_BUS_BLOCK;
END_ADDRESS_SPACE;
////////////////////////////////////////////////////////////////////////

In the above BMM file example the name 'picoblaze1' could be anything. 
Further the label 'top/picoblaze1/myram' is the instantiation name of 
the blockRAM with complete hierarchy.  To obtain the instantiation name 
of the blockRAM you could run the tools one and then open up FPGA Editor 
to see the complete instantiation name of the blockRAM.

The second file you have to add to the Project Navigator project is a 
MEM file.  A MEM file is essentially a HEX file (output from KCPSM 
assembler) with '@0' as the first line.  Currently, you must create the 
MEM file by hand from the HEX file.

Every time the time stamp of the MEM file changes then the 'Generate 
Bitstream' task becomes unchecked in Project Navigator.  All you have to 
do is is Run 'Generate Bitsteam' and the a bitstream will be generated 
with the updated values without running through Synthesis/Translate/MAP/PAR.

Cheers,
Shalin-

Michael Dreschmann wrote:
> Hello,
> 
> in my actual design im using a few picoblazes. Now I wonder if it is
> possible to update the code in the bitstream without a new
> implementation run like it is possible with the microcblaze. I checked
> data2bram but it allows only an update of 16 Bit wide Brams, not the
> necessary 18 Bit.
> 
> Thanks,
>   Michael

-- 
------------------------------
Shalin Sheth
Embedded Applications Engineer
General Products Division
Spartan-3 Generation FPGAs
http://www.xilinx.com/spartan3
http://www.xilinx.com/spartan3e
------------------------------

Hi Michael,

Michael Dreschmann wrote:
> in my actual design im using a few picoblazes. Now I wonder if it is
> possible to update the code in the bitstream without a new
> implementation run like it is possible with the microcblaze. I checked
> data2bram but it allows only an update of 16 Bit wide Brams, not the
> necessary 18 Bit.

The following may be of interest to you (full-text PDF available from 
the link):

http://eprint.uq.edu.au/archive/00002080/

Programmable Parallel Coprocessor Architectures for Reconfigurable 
System-on-Chip.

Williams, John A. and Bergmann, Neil W. (2004)

We propose a hybrid rSoC parallel processing architecture consisting of 
a central 32-bit RISC microprocessor interconnected to an array of 8-bit 
microcontrollers as coprocessing nodes. The central processor runs an 
embedded Linux operating system, with the coprocessor nodes mapped into 
a virtual file system, by which they can be controlled and reprogrammed. 
The hardware and software architectures are detailed, and several useful 
application contexts are proposed. Supporting theoretical analysis is 
also presented.

Regards,

John

John Williams wrote:
> Hi Michael,
> 
> Michael Dreschmann wrote:
> 
>> in my actual design im using a few picoblazes. Now I wonder if it is
>> possible to update the code in the bitstream without a new
>> implementation run like it is possible with the microcblaze. I checked
>> data2bram but it allows only an update of 16 Bit wide Brams, not the
>> necessary 18 Bit.
> 
> 
> The following may be of interest to you (full-text PDF available from 
> the link):
> 
> http://eprint.uq.edu.au/archive/00002080/
> 
> Programmable Parallel Coprocessor Architectures for Reconfigurable 
> System-on-Chip.
<snip>

Impressive.
Did you look at data links between the PicoBlaze units ? - that would
further off-load the main CPU, and ease situations where a single
task proved too much for one Picoblaze ?
-jg

Hi Jim,

Jim Granville wrote:
> John Williams wrote:
> 
>> Michael Dreschmann wrote:
>>
>>> in my actual design im using a few picoblazes. Now I wonder if it is
>>> possible to update the code in the bitstream without a new
>>> implementation run like it is possible with the microcblaze. I checked
>>> data2bram but it allows only an update of 16 Bit wide Brams, not the
>>> necessary 18 Bit.
>>
>>
>>
>> The following may be of interest to you (full-text PDF available from 
>> the link):
>>
>> http://eprint.uq.edu.au/archive/00002080/
>>
>> Programmable Parallel Coprocessor Architectures for Reconfigurable 
>> System-on-Chip.
> 
> <snip>
> 
> Impressive.
> Did you look at data links between the PicoBlaze units ? - that would
> further off-load the main CPU, and ease situations where a single
> task proved too much for one Picoblaze ?

No I didn't, however PicoBlaze interfacing is so simple that adding 
either direct-wired or buffered (FIFO) links between multiple Picos 
should be pretty straight forward.

We since have expanded the concepts in that paper to multi-microblaze 
systems - their native FSL interfaces make it trivial to connect them up 
to each other in arbitrary topologies, and also makes it easy to drop a 
bit of custom hardware in place of a CPU if you decide you need more 
performance or smaller logic utilisation.

BTW, the device driver developed for that work is in the public uClinux 
source tree, it's a generic uClinux driver for FSL peripherals.  So, you 
can interact with pretty much any FSL core from within uClinux, using 
intuitive open/read/write system calls, just like any other file/device.

Regards,

John