Attendees

1. Thomas Watteyne

2. Austin Patel

3. Kristofer PISTER

4. David Burnett

5. Fil Maksimovic

6. Martina Balbi

7. Said Alvarado-Marin

Action items

• Thomas Watteyne to write an nRF UART pass-through snippet
• Thomas Watteyne to write an VDDD tapping snippet
• Austin Patel to coordinate with Andrew Fearing to get 60x boards assembled with a regulator and an IMU
• Thomas Watteyne to work on letter for David Burnett
• Austin Patel to tell David Burnett turn-around time and cost for new board manufacturing

Minutes

• Thomas Watteyne

  • Farnell order (60x XLs, 2x dev boards) should be received on 17 Jun 2021

  • Will hold onto chips, just let me know where we should send it

  • Austin Patel will do!

• Said Alvarado-Marin

  • DotBot runs!

• Martina Balbi

  • BLE-based connectivity working

• Fil Maksimovic

  • LH2: working on calibration using a calibration board (4x LH2 receivers)

  • FPGA: thanks David Burnett for point to https://github.com/PyFive-RISC-V/caravel_pyfive ! implements exactly what was needed, peripheral bus (Wishbone), DMA and HW acceleration

  • David Burnett https://opencores.org/

  • Kristofer PISTER great, as previous experience wasn’t fantastic with other approaches

• Kristofer PISTER

  • VDDD tap: would prefer not haven’t an external regulator, breaks the vision a bit

  • we would like SCuM itself to work as a true single chip

  • do we get different results depending on the test (tapping a wire vs. using a power supply)

  • 2 tests:

    • use a real wire

    • use the nRF:

      • pin to VDDD LDO out

      • high z, set 1, strobe from high z to active output, to high z, emulating tapping behavior

  • David Burnett it that doesn’t work, we can use a voltage divider

  • discussion about previous tests

    • tapped at 1.1V: @aus

    • Austin Patel

      • test 1 leave tap connected, record whether programming works, optical programming, on McCoy with the IMU

      • test 2: remove tap when seeing program running

    • constant 1.8V didn't work; a tap at 1.8V didn’t work (board wouldn’t program)

  • Kristofer PISTER what did we do?

    • Fil Maksimovic program, doesn’t execute, tap, it executes

  • Kristofer PISTER looks like the only difference is the duration of the tap

  • Thomas Watteyne we could use the nRF to vary (sweep) the duration of the tap

  • Kristofer PISTER we need to get the nRF up and running, and try with the 3-wire bus

  • Austin Patel probably the next step is to use the nRF.

    • thoughts: people integrating on micro-robots may only need cold boot

    • low confidence this will work

    • looking to having the board work

  • Kristofer PISTER let’s

    • have Andrew Fearing put a regulator to get things going

    • study this with the nRF by disconnecting the regulator

  • Kristofer PISTER can we put a resistor divider on the board so voltage from nRF goes down to 1.1V

  • Austin Patel another pin which has the voltage divider, do can choose between straight to nRF, or voltage divider

  • Fil Maksimovic use a break-out board of a regulator?

  • Austin Patel will ask Andrew Fearing

  • Thomas Watteyne to write a UART pass-through snippet

  • Thomas Watteyne to write a strobe snippet

• David Burnett

  • writing proposal