Page Comparison

Sept 20

Aashmika + Jess

POWER SELECT

• couldn't repro issue with shdn pin line 287 power_select.c turning the board off briefly (0.5 seconds)

• started checking valid pin readings and they were broken

• checked continuity for all the valid pins + resistors and everything looked fine (no shorts)

• was a bit discontinuous with the controller board plug, resoldered

• valid pins worked after resoldering! note: valid pins are active-low, should change code to reflect that

• voltage reading is consistently wrong but some are more correct than others, hardware to debug vsense pins

• isense are all wrong, scaling factors seem off

babydriver snippet for checking valid pins:
def read_pins():
print('a8', gpio_get('a', 8))
print('a9', gpio_get('a', 9))
print('a10', gpio_get('a', 10))

Sept 26

Aashmika + Jess

BMS CARRIER

• branch: soft_151_bms_validation

• KS doesn't work using smoke_bms. Button works, but not GPIO change observed on KS monitor.

• turning the relays on does nothing
  CURRENT SENSE

• running smoke_ads1259

• scope doesn't show good output at carrier board

• clock seems fine, MOSI seems slightly off

• output was super wavy and hard to read

• spi port 2 seems completely borked, no output

• spi port 1 seems ok

• Tried two different controller boards
  AFES

• vsense works for all three flawlessly!
  POWER SELECT

• resoldered the entire thing

• vsense works now! no scaling factor change

• TODO: tune scaling factors for isense

• TODO: remove jumpstart schematic stuff, 3v3 cell

• TODO: tune temp sense

Oct 1 (Happy spooky season)

Mitchell + Nita

CHARGER:

• Verified that EVSE is outputting power. The LED on the EVSE indicates charge state, and as such was used to debug.

  • When connected and CP pin is low, EVSE is WHITE

  • When the Control Pilot select pin goes high, the impedance changes and the EVSE interprets this and goes into charge mode (BLUE)

• Setup E-Load:

  • Use CV Mode, Set to 100V (and turn on)

• Received CAN messages from ELCON:

  • 12V LED lights up at CAN Socket, indicating that the Elcon has power (SHOULD BE SEEN IF CONFIGURATION IS CORRECT)

  • Sending message with corresponding ID from charger board via prv_periodic_send (every 1s)

  • Receive message of different ID (18FF50E5) from charger, and parse data

• NEXT STEPS:

  • Hardware:

    • Solve control pilot analog read (pin A5) not able to be read by MCU

  • Firmware:

    • Validate control pilot circuit

      • Rewrite module to read analog values from AN5 and AN6, to get both duty cycle (AN5) and amplitude (AN6) of PWM

    • Validate Elcon communication

      • Ensure logic to transmit values is correct, and corresponds to output received by E-Load

Oct 05, 2021

Mitchell

CHARGER

EVSE Control pilot circuit:

What we know now:

• The EVSE (Electrical Vehicle Supply Equipment → ie wall charger) PWM circuit is used to communicate data between EVSE and the Charger Controller board, per J1772.

• By changing the impedance of the circuit by setting a pin state, charger controller can indicate charging state.

• The PWM duty cycle tells us the maximum mains current (not too sure what that is) allowed, according to the following table

Image Added

• There has also been reference to the amplitude of the PWM indicating charging information and our circuit is set up to read this, although I cannot confirm that this value holds any meaning (maybe Nita E can)

Current Implementation:

• The current Implementation reads PWM but this will not work atm as the voltage of the PWM peaks is too low for the MCU to read

• The circuit is designed so that we can read PA5 Analog values which correspond to Duty cycle of the PWM via an RC filter on the PWM input. Verified that PA5 reads non-zero analog values, but haven’t verified that they change as Duty Cycle changes: see next steps

Next Steps:

• To verify PA5 can be used to read PWM Duty Cycle, we need to generate a waveform and read the analog value output. By mapping analog readings->DC values we can create thresholds or a function to detect different current values

• Need to understand whether or not the amplitude of the PWM is needed. If so, adds an additional complication as it cannot be read as an analog input correctly (sampling doesn’t work well on stm32)

Oct 8

Mitch

CHARGER:

Elcon Comms: sent messages to attempt to get power output

• No output available. One of the error flag bits is being set (0b4, 0x8), which the code indicates is a “Voltage polarity error”, but it seems like that bit may indicate a timeout error, will troubleshoot on Sunday

  Image Added

PWM:

• Still no PWM available - Peak Value measured by Nita E was 0.64V, which is less than the 1.85 Vih needed to register a PWM signal, this is most likely the issue.

• Unable to test PWM->analog input at AN5 circuit. Will need to decide whether analog is good enough for now, or if we need a new rev with amplified PWM