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| mithro | xobs: When you are up, I would like to repo your RPi setup with the Hacker tomu's here | 00:28 |
|---|---|---|
| xobs | mithro: sure. I've got half an hour before chinese class. What's up? | 00:39 |
| mithro | xobs: Do I just follow https://git.xobs.io/xobs/fomu-flash ? | 00:39 |
| tpb | Title: xobs/fomu-flash: Utilities to work with Fomu, as attached to a Raspberry Pi - Gitea: Git with a cup of tea (at git.xobs.io) | 00:39 |
| mithro | and which pins do I use? | 00:40 |
| xobs | Ah, for Fomu? Yes. | 00:40 |
| xobs | I probably should add more diagnostics, including the ability to read out the SPI flash ID code. | 00:41 |
| xobs | I'll do that when I'm at the office today and have access to my EVT board. | 00:41 |
| xobs | Let's see... the best way to hook pins up is probably to follow https://git.xobs.io/xobs/tomu-fpga/raw/commit/cd4d928adb3dd68b22ab5da60e4a4d01ee201caf/reference/tomu-fpga-evt2.pdf | 00:42 |
| mithro | xobs: Okay thanks | 00:54 |
| mithro | I'll probably still be around when you get into the office later | 00:54 |
| xobs | mithro: alright. the two features I need to add are (1) the ability to read out the SPI flash ID code, to make sure the connection is good, and (2) a flag to set the SPI mode (single/dual/quad/qpi). | 00:55 |
| mithro | xobs: SGTM | 00:56 |
| mithro | xobs: Your not using this SPI flash that tinyfpga was using? | 00:56 |
| mithro | tinyfpga: ping? | 00:56 |
| xobs | mithro: no, the version tinyfpga is using is a WLCSP that's designed to be super small. I went with an 8USON that's slightly larger, but has second sources, as well as slightly larger capacity. | 00:57 |
| xobs | I'd love to be able to go with a larger 8USON, though. The one I picked is 3x2mm, but there are some 4x4mm ones that have more storage capacity. | 00:58 |
| mithro | xobs: IIRC the tinyfpga has a special register that has to be written to get QSPI mode... | 00:59 |
| xobs | mithro: I'd imagine that's standard. fomu-flash does that, too: https://git.xobs.io/xobs/fomu-flash/src/branch/master/spi.c#L394 | 01:00 |
| tpb | Title: xobs/fomu-flash: Utilities to work with Fomu, as attached to a Raspberry Pi - spi.c at master - Gitea: Git with a cup of tea (at git.xobs.io) | 01:00 |
| mithro | xobs: I know picosoc needed something specially for it | 01:00 |
| xobs | yeah, it took me a while to find that. much frustration. otoh, now I understand QPI and quad spi much better now. | 01:06 |
| mithro | xobs: Should I add tomu-evt to LiteX-BuildEnv? | 01:18 |
| xobs | mithro: that would be nice, thanks! what do you need to do that? | 01:22 |
| xobs | I have a local version that I've been working with. it's a bit of a lie, because I run the 48 MHz oscillator through a PLL and call it "12 MHz", so I'm not entirely happy with my solution. | 01:23 |
| mithro | xobs: I'm using the internal 48MHz oscillator at 12MHz | 01:34 |
| xobs | mithro: I'm still learning FPGAs -- can you just pull out bit 2 and run it into a clock buffer? Is that stable enough to actually work at those frequencies? | 01:35 |
| mithro | xobs: The oscillator has an internal divider | 01:36 |
| xobs | mithro: ah! you run the internal 48 MHz oscillator through a divider, not the crystal. clever. | 01:37 |
| mithro | xobs: I'm just doing a little rebasing | 01:38 |
| cr1901_modern | $cr1901cc -pedantic | 01:44 |
| cr1901_modern | Below 50Mhz, it's not gonna matter, but one should really not use a FF divider to do clock division. | 01:44 |
| cr1901_modern | skew will result so it's difficult to relate the phase of your divided clock to the source clk | 01:44 |
| xobs | cr1901_modern: thanks for the info. That was my gut feeling, too. | 01:53 |
| mithro | xobs: Generally it's pretty hard to route clocks into/out of the logic | 01:57 |
| mithro | xobs: Do you have a tinyfpga_bx ? | 02:02 |
| xobs | mithro: I don't think I do, no. Why do you ask? | 02:03 |
| mithro | xobs: It would be good for someone to replicate the USB that currently works | 02:03 |
| xobs | mithro: today I'll give it a shot on Fomu. Better test it before the campaign starts... | 02:04 |
| mithro | xobs: I need to figure out what I've done wrong as the usb core is not meeting timing on the up5k | 02:05 |
| mithro | xobs: Would be good to test lm32+picorv32+vexriscv on the Fomu too... | 02:05 |
| xobs | I got lm32 micropython working. | 02:07 |
| mithro | xobs: Seem mithro/litex-buildenv/tinyusb-work | 02:07 |
| xobs | I tried building a smaller vexriscv, and the result was just the top line of the bios prompt before it froze. | 02:08 |
| xobs | That was using my own Scala file, though. | 02:08 |
| mithro | xobs: I just rolled forward litex, so litex-buildenv should have Florent's minimal vexriscv versions in it now | 02:09 |
| cr1901_modern | xobs: Lemme know if the minimal vexriscv versions work. I've had trouble w/ minimal vexriscv last time I tried it on ice40. | 03:05 |
| xobs | mithro: I just added the "-i" and "-t" parameters to fomu-flash. | 03:10 |
| xobs | The "-i" parameter reads every ID code it can find. Use that to make sure your connection is good. | 03:10 |
| xobs | The "-t" parameter takes one of four options: 1, 2, 4, or q. It sets the SPI bit width. | 03:11 |
| xobs | So try "-t 1" for now. | 03:11 |
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| mithro | xobs: okay, will test after I grab some dinner | 03:21 |
| xobs | mithro: also, I'm grabbing your latest tinyusb work. I'll try to get it working on Fomu! It uses lm32, right? | 03:22 |
| mithro | xobs: At the moment, but it should be easy to port to vexriscv / picrorv32 | 03:23 |
| xobs | alright, then in the interest of not changing too much at once, I'll stick with lm32 | 03:23 |
| mithro | xobs: I haven't tested on the up5k yet | 03:23 |
| xobs | ...that's worrisome. "Info: ICESTORM_LC: 5169/ 5280 97%" | 03:36 |
| mithro | xobs: What config are you using? | 03:46 |
| xobs | I was using lite, but now I'm retrying with minimal. | 03:47 |
| mithro | xobs: Mine is in the 4k range | 03:47 |
| xobs | 4883 (92%) with minimal lm32. Still doesn't route, though. Much better! | 03:51 |
| xobs | Is there an example of a litex target that doesn't have ROM, but boots from RAM instead? | 04:15 |
| xobs | I'll just add ROM as a mirror of RAM. | 04:19 |
| mithro | xobs: https://github.com/mithro/litex-buildenv/blob/tinyusb-work/targets/tomu_fpga_hacker/base.py | 04:20 |
| tpb | Title: litex-buildenv/base.py at tinyusb-work · mithro/litex-buildenv · GitHub (at github.com) | 04:20 |
| mithro | xobs: That is XIP from spiflash, no rom | 04:21 |
| xobs | I pulled out SPI and it managed to route. | 04:24 |
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| xobs | What's the best way to access a Verilog signal? I'd like to wire soc_lm32_dbus_adr[2] up to an IO pin. What I'd really like to do is assign pmod_n0 <= soc_lm32_dbus_adr[2] | 05:55 |
| mithro | xobs: That I'm not sure about | 06:14 |
| xobs | daveshah (or anyone): do you know if the UP5K bitstream supports SPRAM configuration? | 06:44 |
| mithro | xobs: It does not | 06:55 |
| * xobs gets distracted fitting the bios into 8kB of RAM... | 08:33 | |
| xobs | Okay, so I now have a boot prompt, and I have just about everything working from a UX perspective. The only command that doesn't work is "wcsr", because that blows out the 8 kB image. | 08:59 |
| xobs | mithro: Should I load some program from third_party/valentyusb/third_party/tinyusb/examples/? | 09:00 |
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| xobs | Okay, I managed to get the bios to work mostly, though I need to change the memory offsets. The spiboot command ends up overwriting the bios memory due to overlaps. | 10:53 |
| xobs | The cool thing is that this now fits in the Bitstream, so no need for flash memory. | 10:54 |
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