<sb0>
whitequark, how is the artiq error reporting coming along?
ohama has quit [Ping timeout: 250 seconds]
ohama has joined #m-labs
<mithro>
sb0: how do you work out the nrows and ncols values for a SDRAMModule? - Is it just 2**(number or row address with) and 2**(number of col address with)
<sb0>
yes
<sb0>
sdrams come in power-of-two dimensions
* sb0
just received a small pack of new vacuum gear from china that cost 15% of the european/us prices and looks perfect
* sb0
is starting to believe the "$1000 MPW ASIC run" stories
<mithro>
sb0: I'm unsure about the correct way to solve that error.
<sb0>
the only thing I haven't found yet is turbomolecular pumps. seems to be all US/EU imports, and they imported the prices too.
<sb0>
maybe the "foreign experience absorption" didn't reach that yet
<mithro>
The pipistrello that I'm "copying" from uses Mobile DDR IOSTANDARD for the ddr clock pins
<sb0>
mithro, are you actually trying to output a differential signal?
<sb0>
is the clock also differential on "mobile" ddr? i guess so....
<sb0>
you should use a OBUFDS primitive
<sb0>
which can be produced by the new portable DifferentialOutput in migen
<mithro>
It looks like Mobile DDR is single ended
<mithro>
I see where IBUFG and IBUFDS type things are being created but I don't see where / how the OBUFDS should be created - I don't see any OBUF or similar
<sb0>
then you should not attempt to drive it with a differential iostandard
<sb0>
nor use a obufds
<sb0>
you should not use obuf. obufds replaces the obuf.
<sb0>
obufds should have its differential pins connected directly to the io pads in the netlist
<sb0>
(which can be done in the same way in the hdl, since xst will refrain from inserting obufs then)
<mithro>
The pipistrello uses Mobile DDR (which is single ended), the Atlys uses DIFF_SSTL18_II - so I thought I should need to change a OBUF to OBUFDS right? I don't see any OBUFDS examples in misoc/targets - so not sure the correct way
<mithro>
Looking at the pipstrello, it looks like its using two ODDR2 to produce a diff clock - so I should just replace those with an instance of OBUFDS similar to the example I found in k7addrphy.py
_florent_ has joined #m-labs
<mithro>
actually, if I do that, I get the warning about driving clocks onto IO lines, so have to used the ODDR trick
<mithro>
_florent_: hello!
<_florent_>
hi
<mithro>
I'm slowly trying to get LiteEth working on the Atlys board
<_florent_>
cool, is it going well for now?
<mithro>
_florent_: not yet at a stage where I really have anything to show
<mithro>
_florent_: still trying to figure out the misoc/platform/xxx.py stuff
<mithro>
_florent_: opps, I mean the misoc/targets stuff - basing it off a mixture of the kc705 and pipistrello configs
<mithro>
---> Bitstream generation is complete. !!
<_florent_>
suspense... :)
<mithro>
so, once I have a bitstream, how do I "test" ?
<mithro>
I seem to remember previously uploading the bitstream and seeing something on a uart
<mithro>
but I think that was FramebufferSoC rather than the MiniSoc I've been working with?
<sb0>
mithro, is it a real differential standard?
<sb0>
on the pipistrello
<sb0>
like lvds or such
<sb0>
I'm not sure what sort of skew you can get between the two ODDR2s and whether this is a problem or not... i'd recommend using OBUFDS when possible
<mithro>
sb0: I'm using an ODDR2 -> OBUFDS
<sb0>
that should work I think
<mithro>
sb0: so - now I have a bitstream, I should just load it onto my board and look for output on the serial port?
<ysionneau>
mithro : do you embed some code to execute in ROM? or do you execute from spi flash (XIP)?
<mithro>
ysionneau: If the default kc705.py doesn't do that - then no
<ysionneau>
then just flashing the bitstream isn't enough, you should also flash some BIOS code to execute if you want to see some UART output
<mithro>
ysionneau: so - how do I do that? :P
<ysionneau>
sorry *bbl*
<mithro>
What is the diffrence between
<mithro>
./make.py -t digilent_atlys all and ./make.py -t simple -p digilent_atlys all
<mithro>
previously there seemed to be a way to use the BRAM preloaded with code - IntegratedBIOS or something?
<mithro>
anyway, time for me to brave the cold rainy weather and walk home
<mithro>
appreciated feedback and on how to move forward from here
<ysionneau>
14:37 < mithro> previously there seemed to be a way to use the BRAM preloaded with code - IntegratedBIOS or something? < yes, IntegratedBIOS allows you to embed the BIOS in the bitstream thus you don't need to use the spi flash and can reduce the potential bugs when bootstraping a new board
<sb0>
it's -Ot integrated_rom_size XXXX now
sh[4]rm4 has joined #m-labs
sh4rm4 has quit [Ping timeout: 265 seconds]
<_florent_>
mithro: I think it will be easier for you to do smaller steps for your port:
<_florent_>
Get the simple target working with the Altys
<_florent_>
(only requires a clock and rx/tx uart lines)