| *** tpb has joined #litex | 00:00 | |
| *** spacekookie_ has joined #litex | 00:28 | |
| *** st-gourichon-f has joined #litex | 00:29 | |
| *** karol has joined #litex | 00:30 | |
| *** pbinkowski1 has joined #litex | 00:30 | |
| *** spacekookie has quit IRC | 00:31 | |
| *** nn_ has joined #litex | 00:32 | |
| *** st-gourichon-fid has quit IRC | 00:34 | |
| *** kgugala has quit IRC | 00:34 | |
| *** pbinkowski has quit IRC | 00:34 | |
| *** rvense has quit IRC | 00:34 | |
| *** _whitelogger has quit IRC | 01:18 | |
| *** _whitelogger has joined #litex | 01:20 | |
| *** spacekookie has joined #litex | 03:20 | |
| *** kbeckmann2 has joined #litex | 03:24 | |
| *** spacekookie_ has quit IRC | 03:28 | |
| *** kbeckmann1 has quit IRC | 03:28 | |
| *** _whitelogger has quit IRC | 04:36 | |
| *** _whitelogger has joined #litex | 04:38 | |
| *** _whitelogger has quit IRC | 06:48 | |
| *** _whitelogger has joined #litex | 06:50 | |
| *** _whitelogger has quit IRC | 08:12 | |
| *** _whitelogger has joined #litex | 08:14 | |
| *** HEGAZY has joined #litex | 10:28 | |
| *** nn_ is now known as rvense | 11:57 | |
| *** karol is now known as kgugala | 12:28 | |
| *** scanakci has quit IRC | 13:20 | |
| somlo | so, after RTFMing a bit on the "mmcme2_adv" and "dcm_clkgen" blocks from xilinx, it doesn't look like "ehxplll" on ecp5 can set up for a progammable output frequency | 14:13 |
|---|---|---|
| somlo | which means that on ecp5 we'll have a hardcoded sdcard clock that won't be software-adjustable | 14:13 |
| daveshah | Yeah, there's no real programmability | 14:14 |
| somlo | on the bright side, it should be simple to set up for this n00b :) Downside being it won't be as awesome as it is on xilinx... | 14:16 |
| somlo | going completely off on a tangent, I don't quite understand the point of an adjustable sdcard clock frequency -- why not just pick the largest value that makes sense (as close to 50MHz as possible) and enjoy? :) I'm sure I'm missing something, but I don't know what... | 14:22 |
| somlo | this might be a question for _florent_, if/when he checks his IRC backlog... | 14:22 |
| _florent_ | somlo:the SDCard initialization need to be done at a low frequency. The current clocker module is using a PLL, because i wanted to evaluate the max frequency we were able to achieve, but we could have something that just has 1 clock and a clock divider for the initialization. | 14:44 |
| somlo | _florent_: by "SDCard initialization" do you mean running the sdcard_init() routine in the bios, or something else that happens in the gateware? | 15:08 |
| *** HEGAZY has quit IRC | 15:35 | |
| *** HEGAZY has joined #litex | 16:56 | |
| *** CarlFK has quit IRC | 17:20 | |
| *** HEGAZY has quit IRC | 17:48 | |
| Claude | Sounds like bios , because the actual card initialisation must indeed with maximum 400khz card clock | 17:53 |
| Claude | After that init the card answers back the highest frequency it supports | 17:54 |
| Claude | Or one can ask the card .. better said | 17:54 |
| *** CarlFK has joined #litex | 18:14 | |
| somlo | Claude: then the "set-clock -> init -> test" sequence here: https://github.com/enjoy-digital/litesdcard/blob/master/README#L82 is probably not telling the whole story | 18:43 |
| tpb | Title: litesdcard/README at master · enjoy-digital/litesdcard · GitHub (at github.com) | 18:43 |
| somlo | we set the sd clock to 10MHz, initialize, then test. I've successfully set the clock to 50, initialized, and tested :) | 18:44 |
| somlo | seems like it should be 1. set clock to 10MHz; 2. init; 3. set clock to maximum (as per card init results; 4. test/use/whatever | 18:45 |
| somlo | anyway, for now I'll try to get ecp5 working with a 10MHz fixed clock, then we can add the option to switch to something faster later down the road | 18:47 |
| somlo | one more thought/question: I was able to successfully run sdinit on all my cards (even the ones that subsequently failed the test), and I was able to successfully sdinit them all at *any* frequency from 10 through 50 MHz | 18:49 |
| somlo | is that just the cards being permissive, but not something I should rely on (per the sdcard specs, which I have admittedly *not* read)? :) | 18:50 |
| *** CarlFK has quit IRC | 19:10 | |
| *** kbeckmann2 is now known as kbeckmann | 19:30 | |
| *** kbeckmann has joined #litex | 19:30 | |
| *** CarlFK has joined #litex | 19:46 | |
| awygle | cards are usually fine with initialization at whatever frequency, but it's technically in violation of spec to ask them to be. | 20:47 |
| awygle | you're supposed to come up in "compatibility' mode which is <400 kHz clock iirc | 20:47 |
| *** awygle has quit IRC | 21:07 | |
| *** awygle has joined #litex | 21:19 | |
| somlo | awygle: yeah, that was my guess, thanks for confirming! | 21:36 |
| awygle | as florent said what we usually do is run a max-rate clock and a clock divider. All internal logic runs at max-rate, the divider only affects the output. | 21:37 |
Generated by irclog2html.py 2.17.2 by Marius Gedminas - find it at https://mg.pov.lt/irclog2html/!