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End of break meeting for figuring out what to do
WHat The STM
which pins are gpio and which can only have certain functions to make sure no conflicts
STM cube it out
ESD
redo ESD
have unidirectional, want bisexual ESD protection
Accelerometer
no more hi and low g, just medium G
lsm6dso
✅completed✅
Buzzer
switch to transistor with lower or no pulldown
jimfluence The digital transistor on the buzzer is going to current limit it to 7mA or so, versus the 22.5mA it needs to run. If I am reading the datasheet right, you have a gain of 35, and when you pair that with the 10k base current-limit resistor and the 10k base pulldown resistor, you get something like this;
https://falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxAUgpABZsKBTAWjDACgAXEFPPb-ENmyF+fKhCY1o2BDXSRiYQpEJhsKKNEI0EpDMXzZi2PITwQZIACYMAZgEMArgBsObAE7deon2jHJ4Dy8+P2DuDA1xeEg2AHcwzA0hEUSoOMFhcKTMlBQaNIBzDJSI4rCqGIAZXwEwHh9xEAdnAGcGQWk0gA9BBAgUOopVbjAkfLyQAAsAMQBRAB0WmUWAdQB7dxaOJgBheza2ACUysBp85PBBitoqJGuYBHSL0-PMsGJItjWQYhBtKEEZhw1BgkBQd24P0EbCAA https://rit-launch-initiative.slack.com/archives/C02RSVD8US2/p1736117788785479?thread_ts=1736117574.819669&cid=C02RSVD8US2 If you swap it for a digital transistor that has no pulldown (like the LMUN2215LT1G) or one that has a much weaker pulldown than current-limit (like the LMUN2233LT1G) that would probably fix your issue, but run the numbers on the gain to be sure
STM Power
Vref, Vcap1, Vcap2 (idk what all these Vs mean(can you tell the EE is not taking these notes))
Nat is reading the datasheet as we speak
Nat read the datasheet and we're chilling
✅completed✅
Altium Comments look at em
Figure out that sensor ICs are still available on JLCPCB/Digikey
Jellybean Circuit? for making sure stuff doesnt explode on reset
WIP
RC Low Pass Filter was suggested
POR Manager/Watchdog timer also suggested
Go back to having safety screw switch like original presentation
The EEs cooked.
completed
Decisions since Schematic Review
Replace LSM6DSL+ADXL375 with LSM6DSO32
uhh Jlelyebans in the circuits? nat help
Schematic Review 1 Updates
ADXL375 runs at Bus speeds. Higher bus speed → higher data rate
Maybe getting jimfluenced into using a +/- 32 g accelerometer so we have the same high g low g acc. After boost happens, drop range to +/- 4g for higher precision https://www.st.com/en/mems-and-sensors/lsm6dso32.html
Need bisexual ESD protection - was screwing with rs485 + ethernet
Update buzzer schematic. (Choose a passive buzzer, P chanel switching or charge pump with n channel to make sure it actually switches)
Grim pins float on flashing/bootup? might explode the rocket
and gate with delayed power? i think thats what jim said
check for FUSA AEQ rating for functional safety: pins dont go high until you tell them
Bens Deployment schematic works but we got lost in the sauce and lost it in altium
Updates since presentation
Using stm32f7 - easier to integrate + still has all the features we need
QSPI flash to mitigate data storage rate worries from grim
STLink MINIE instead of STLink MODS. Less space taken up on board technically less features but covers the features we were planning to use on mods. Maintains compatibility with j-links as theres stdc14 to jtag connectors.
Selected LAN8742A for PHY transceiver. Used on the nucleo for the f7 and we’re going to steal their circuit1
Move BME280, LSM6DSL, ADXL375 to SPI (they all have zephyr drivers and have proven to lock up our i2c bus). MS5611 and INA260 stay on i2c bc we either sample them very slowly or don’t wanna write a SPI driver for MS5611.
Presentation Notes
Do we want to make the 2 P-IO pins on i2c pins or PWM pins (routing)
Old temperature Requirements (10F-110F) were silly
0C-50C is prolly good
Pick requirements for sensors more betterly
Gyro: Small angular random walk
How would it work if we lost power? -dean
Altimeter boost detect would probably still work
IMU boost detect wouldnt
Just dont loose power lol
Configurability in field
really vague requirement (telling aaron to reflash them is configurabililty in field)
has a console to reconfigure - better way to say that
Don’t need arming switch
Make boost detect requirement verify by test
Conops was not a conops
wiring was a little nasty
DE9 Pin shenanigans
2x ematch
2x rs48
2x PIO
5v
GND
ematch bypassbreaking out kinda sketchy
but we need to break it out anyways so
BMP388 vs 390. which one is available
board space might be tight
make a harness diagram for a de9
Little plane whats the deal with that
sketchy header thingy to power mod would work
stlink cut first
takes up a lot of space
dont have compatibility with jlink
is convenient tho
Leds should run at 3.3V
Double check buzzer stuff
can it actually make music
...