clifford changed the topic of #yosys to: Yosys Open SYnthesis Suite: http://www.clifford.at/yosys/ -- Channel Logs: https://irclog.whitequark.org/yosys
emeb has left #yosys [#yosys]
gsi_ has joined #yosys
gsi__ has quit [Ping timeout: 245 seconds]
_whitelogger has joined #yosys
_whitelogger has joined #yosys
_whitelogger has joined #yosys
lutsabound has quit [Quit: Connection closed for inactivity]
pie__ has joined #yosys
pie___ has quit [Ping timeout: 272 seconds]
chaseemory has quit [Quit: Lost terminal]
cr1901_modern has quit [Read error: Connection reset by peer]
cr1901_modern has joined #yosys
rohitksingh has joined #yosys
_whitelogger has joined #yosys
leviathanch has joined #yosys
rohitksingh has quit [Ping timeout: 246 seconds]
_whitelogger has joined #yosys
emeb_mac has quit [Ping timeout: 245 seconds]
leviathanch has quit [Remote host closed the connection]
seldridge has quit [Ping timeout: 246 seconds]
rohitksingh has joined #yosys
m4ssi has joined #yosys
rohitksingh has quit [Ping timeout: 244 seconds]
keesj has joined #yosys
m4ssi has quit [Remote host closed the connection]
rohitksingh has joined #yosys
leviathanch has joined #yosys
rohitksingh has quit [Ping timeout: 246 seconds]
rohitksingh has joined #yosys
citypw has quit [Ping timeout: 245 seconds]
ZipCPU has joined #yosys
citypw has joined #yosys
rohitksingh has quit [Ping timeout: 245 seconds]
jevinskie has joined #yosys
tmeissner has joined #yosys
dpiegdon has joined #yosys
<dpiegdon> hi there!
m4ssi has joined #yosys
<dpiegdon> i have been playing around with ringoscillators, and found a working example from clifford, at http://svn.clifford.at/handicraft/2015/ringosc .
<tpb> Title: handicraft - Revision 2994: /2015/ringosc (at svn.clifford.at)
<dpiegdon> I was able to get this running with arachnepnr easily,
<dpiegdon> but on nextpnr, which is timing driven, I always get the error: ERROR: timing analysis failed due to presence of combinatorial loops, incomplete specification of timing ports, etc.
<dpiegdon> which makes sense, I guess. but is there a way to tell nextpnr to ignore timing here? or alltogether?
<dpiegdon> (I have tried --no-tmdriv)
lutsabound has joined #yosys
<daveshah> dpiegdon: use --force
<dpiegdon> daveshah: ok, then the error is reduced to a warning, but no output file is generated.
<daveshah> What is your full command line?
<dpiegdon> nextpnr-ice40 --no-tmdriv --force --hx1k --package tq144 --pcf icestick.pcf --json $<
<dpiegdon> i have uploaded my example to https://github.com/dpiegdon/ringoscillator
<tpb> Title: GitHub - dpiegdon/ringoscillator: FPGA ringoscillator example. Originally taken from http://svn.clifford.at/handicraft/2015/ringosc/ (at github.com)
<daveshah> You need --asc output.asc to create any output
<dpiegdon> damn - copy and paste error
<dpiegdon> thanks!
<dpiegdon> yes, that works. ringing at 322MHz :)
brasilino has joined #yosys
<MoeIcenowy> by the way is it a way to evalulate the frequency of such a ring oscillator?
<MoeIcenowy> can icetime do it?
<sorear> with the icetime database it is possible to produce a conservative lower limit for the frequency (upper bound on delay of the closed-loop path)
<sorear> ring oscillators are very sensitive to things like temperature (and are frequently used as sensors)
<sorear> a more sophisticated timing analysis (for hold times) would also give you a lower bound on the delay → upper limit for the frequency over the operating voltage/temperature range
m4ssi has quit [Remote host closed the connection]
fsasm has joined #yosys
<dpiegdon> but icetime does not produce valid results here. neither for nextpnr nor for arachnepnr. it *did* produce some valid results for an earlier example. i am going to look into this a bit.
<dpiegdon> so for the original version from clifford, icetime shows the (~correct) value of 8.92 MHz. but only when using arachnepnr, not for nextpnr. also when reducing the delay line, the value is rougly the lower bound, as described by sorear.
<dpiegdon> but when i strip the example to only the ring oscillator (remove freq counter and control), icetime is clueless and shows 0MHz.
<dpiegdon> the oscillator *does* work, though
<dpiegdon> so i assume icetime does somehow uses the freq-counter logic loop to count the generated frequency.
emeb_mac has joined #yosys
seldridge has joined #yosys
harryinashed has joined #yosys
harryinashed has quit [Quit: Page closed]
harryinashed_ has joined #yosys
fsasm_ has joined #yosys
harryinashed_ has quit []
harryina_ has joined #yosys
fsasm has quit [Ping timeout: 246 seconds]
harryina_ has quit [Client Quit]
harryina_ has joined #yosys
harryina_ has left #yosys [#yosys]
harryina_ has joined #yosys
harryina_ has quit [Client Quit]
seldridge has quit [Ping timeout: 245 seconds]
tmeissner has quit [Quit: Textual IRC Client: www.textualapp.com]
brasilino has quit [Quit: Leaving]
leviathanch has quit [Remote host closed the connection]
emeb_mac has quit [Ping timeout: 268 seconds]
emeb has joined #yosys
dpiegdon has quit [Quit: leaving]
dpiegdon has joined #yosys
dpiegdon has quit [Quit: leaving]
cr1901_modern has quit [Ping timeout: 272 seconds]
chaseemory has joined #yosys
fsasm_ has quit [Ping timeout: 240 seconds]
s_frit has quit [Remote host closed the connection]
cr1901_modern has joined #yosys
s_frit has joined #yosys
tpb has quit [Remote host closed the connection]
tpb has joined #yosys