S02 E12
18 Apr 2022/02:07:10

More Tales from the Bringup Lab

Oxide and Friends Twitter Space: April 18th, 2022

More Tales from the Bringup Lab
We've been holding a Twitter Space weekly on Mondays at 5p for about an hour. Even though it's not (yet?) a feature of Twitter Spaces, we have been recording them all; here is the recording for our Twitter Space for April 18th, 2022.

Some of the topics we hit on, in the order that we hit them:

  • @2:25 Overview of upcoming themes related to the bringup lab
  • @4:28 Defining the different terms and code-names of the hardware in development at oxide
  • @4:40 Gimlet, the compute node
  • @5:10 Sidecar, a board based on a switching ASIC from Intel
  • @7:24 Arjen's twitter thread with details related to the bringup and Eric's description of the challenges in designing the PDN (Power Delivery Network) ATT
  • @15:34 The load-slammer, an electronic load to simulate the power draw of an ASIC / BGA-part LS
  • @19:06 Bouncing supply cables on load steps
  • @22:27 FPGA that controls everything on the Sidecar board
  • @24:05 TOML's unstable table order made the team pop a couple ICs off the board searching for bugs
  • @31:41 Brown-out in the hotel during first bringup session from a blown bus duct
  • @33:45 Debugging ground bounce issues while testing the PDN with the load-slammer (phantom over/undershoot)
  • @40:15 Hardware team pranks the management during a meeting with a potential investor
  • @43:20 Chonky heat sink that weighs 8 pounds / moment arm crisis
  • @48:19 First time powering up, checking temperature with thermal camera, learning about "puppy dog warm"
  • @52:12 Matt talks about the second, "lesser" network switch on the Sidecar board
  • @57:28 Secret 8051 cores, slew-rate woes: impedance missmatch on SPI traces that manifested in unreliable communication in full bandwidth mode of the SPI/GPIO driver
  • @1:03:19 PLL config issues and Matt's verbose config tool to fix them
  • @1:04:26 Load-bearing dongles
  • @1:06:37 Debugging PCIe link, Arjen's Frankenstein PCIe analyzer/exerciser
  • @1:22:36 Gimlet, stumbling blocks found in January
  • @1:30:08 Arjen's big breakthrough on the Sidecar, shouting at the T6
  • @1:32:08 Cursed pull-downs, Rick's remote hardware debugging support by incrementally breaking his T6 boards to find issue with the DUT
  • @1:36:24 T6 finally comes out of reset, "we're gonna live! we're gonna live!"
  • @1:41:06 Rick reworks gnarly footprint error, on multiple ICs, to verify design for Rev. B - dead bug style.
  • @1:53:12 Sidecar progress continuation, cable oupsi, off-by-one error
  • @1:59:42 Dedicated support by IC vendor with very understanding wives
  • @2:01:20 Summary and parting thoughts
If we got something wrong or missed something, please file a PR! Our next Twitter space will likely be on Monday at 5p Pacific Time; stay tuned to our Twitter feeds for details. We'd love to have you join us, as we always love to hear from new speakers!