IRC logs for #openrisc Tuesday, 2016-09-27

--- Log opened Tue Sep 27 00:00:30 2016
olofkVerilator is many many times faster than an event-based sim such a s icarus or modelsim06:17
olofkDoes anyone have a simple CDC component for Wishbone b2?07:05
olofkOr whatever it's called07:06
olofkDon't need bursts07:06
ZipCPU|LaptopHmm ... I might ask the same question, but I want bursts ;)07:29
ZipCPU|Laptopkc5tja: I can often run 300k clocks/second in Verilator, for a device that is supposed to be run at 1MHz.07:30
ZipCPU|LaptopAs for MAME, I still stand in awe of the Digilent employee who got Pacman running on a Basys-3---a board with too little memory for an offscreen buffer.07:31
kc5tjaolofk: re: Verilator being faster than iverilog -- yes, I know as much.  I don't know quanlitatively *how* much faster though.  Anyway, I use iverilog because it's *way* easier to get working (I'm still unsuccessful getting verilator work, though I haven't put much effort into it), which makes it absolutely perfect for TDD-type development of Verilog.11:13
kc5tjaThat's why I am thinking of using iverilog for unit development purposes, and Verilator for integration testing, which tends to require more resources to complete since they're covering both positive and negative test cases.11:13
kc5tjaZipCPU|Laptop: That's a good data point to keep in mind.  I'll bank on 300kHz real-world speed when trying to calculate time resources needed to run tests.11:14
kc5tjaZipCPU|Laptop: How did Digilent Dude do it?  A/B scanline buffers, a la Atari 7800's MARIA chip?11:15
kc5tjaolofk: What even is a CDC?11:18
ZipCPUkc5tjz: CDC = Clock domain crossing.11:33
ZipCPUAs for Pacman & Basys-3 ... I'm still hoping to find out.  I've asked, but haven't gotten an answer other than it was done.11:33
ZipCPURE: Verilator ... you may find that you need to get rid of the always @(<non-clock-signals>) structures.  I'm not sure if Verilator supports them--at least, I think I remember the last time I tried to coach you through verilator, these may have been the problem.11:35
ZipCPUAs for all others who may know verilator better than I: Please correct me if I am wrong here.11:35
olofkAll right. My basic CDC seems to work now11:49
olofkNo burst or pipeline support, but I only need it to read and write single control/status registers in another clock domain11:49
olofkWhen in doubt about CDC, always consult Clifford Cummings11:50
olofkI think that his document on CDC strategies must be one of those documents I have read most times.11:50
wallentoolofk, yes its excellent12:34
wallentoall code you can find is based on it12:34
-!- Shentino2 is now known as Shentino12:41
ZipCPUolofk: Wow, my CDC search (which I did before your request) also lead me to Clifford Cummings' document.12:47
-!- Netsplit *.net <-> *.split quits: poke5328213:28
-!- wallento_ is now known as wallento15:36
-!- wallento_ is now known as wallento15:45
ams`juliusb: any idea why is down? (when you in the north pole for beer?)15:57
olofkams`: They switched ISP16:08
ZipCPULooks like OpenCores is back up and running!22:09
--- Log closed Wed Sep 28 00:00:32 2016

Generated by 2.15.2 by Marius Gedminas - find it at!