Matt Thompson

4.2K posts

Matt Thompson

Matt Thompson

@fuzziphy

“The measure of intelligence is the ability to change” -Albert Einstein

British Columbia, Canada Katılım Ağustos 2013
508 Takip Edilen769 Takipçiler
Matt Thompson
Matt Thompson@fuzziphy·
@embedrapp @ratatui_rs 37fps. The procedural glyphs are generated offline with a LUT map and baked into firmware with include_bytes, and loaded into the display SDRAM once at init. The RA8876 takes 16 bit user character codes and blits the glyph at the text cursor position
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Embedr
Embedr@embedrapp·
@fuzziphy @ratatui_rs sending cell diffs over DMA for an embedded TUI is absolute wizardry. how's the refresh rate holding up with those procedural glyphs?
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Matt Thompson
Matt Thompson@fuzziphy·
Playing with a 1200x600 SPI display. Wrote an embedded_hal_async driver for its text mode, loaded up procedural glyphs in CGRAM for block/braille chars, and wrote a @ratatui_rs backend to sends cell diffs over a channel to DMA SPI commands. Things you can do in a day using rust
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Matt Thompson
Matt Thompson@fuzziphy·
@orhundev @ratatui_rs This is using a native text mode of an RA8876, so it’s not using embedded-graphics. It’s a custom driver/backend that sends cursor positions, RGB color, and character codes to the controller, and the hardware blits the glyph from CGRAM to a canvas within its own SDRAM.
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Matt Thompson
Matt Thompson@fuzziphy·
@purusa0x6c Libtorch is good, but python is terrible. There are alternatives more appropriate for manipulating huge amounts of data that don’t involve an interpreter and fragile duck typing. Check out Burn.
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i2cjak
i2cjak@i2cjak·
gun pointed at yo head, favorite PCB thickness
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Matt Thompson
Matt Thompson@fuzziphy·
@ThrillaRilla369 Pac-Man, frogger, BubbleBobble, QBasic Gorillas, Zaxxon, Maniac Mansion, Space Quest, Leisure suit Larry, kings quest, doom, duke nukem.. the list could go on
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Thrilla the Gorilla
Thrilla the Gorilla@ThrillaRilla369·
For those who played video games between 1985 and 1995, what's the video game from that time that sticks with you the most, and why
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Elma
Elma@oelma__·
But are you floppy disk old..
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Matt Thompson
Matt Thompson@fuzziphy·
@richmooreiv @Adriksh With some exception where it better to pass by value, as a pointer is 8 bytes and a dereference has cost. If your struct is <= 8 bytes, then typically pass by value.
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Matt Thompson
Matt Thompson@fuzziphy·
@richmooreiv @Adriksh A reference is a pointer. JavaScript abstracts that away and the interpreter does bounds checking. If you “passed” structs in C, you’re deep copying them, and they can only exist on the stack. If you allocate heap, that is a pointer, and passing by value would copy onto stack
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Adriksh
Adriksh@Adriksh·
C pointers were invented because a systems engineer decided that instead of just passing the data, it would be much funnier to hand a junior dev the exact geographic coordinates of a landmine in ram.
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kache
kache@yacineMTB·
My responsibility is to build something so otherwordly that it becomes a product class of its own. I could have gotten a "good enough" result by doing what everyone else would have done, to close sales, and bullshitted clients into thinking it was special. But thats not my goal
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circuitguy
circuitguy@ScottCircuitguy·
@willreil MDF is the most machinable "wood." Whatever you do, don't use K3. Another good option for learning, and it's much less messy, is "Puck Board" which is HDPE.
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Will
Will@willreil·
It's time to become a machinist. I need to go to the hardware store to get some wood that I can use for practice.
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kache
kache@yacineMTB·
pytorch is over. it's done. no one is using it anymore. keep up
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Celeus
Celeus@CeleusWasTaken·
@yacineMTB What a few weeks in embedded does to a man
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kache
kache@yacineMTB·
at the end of the day, c is the only thing serious people use
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Matt Thompson
Matt Thompson@fuzziphy·
@georgecurtiss @Asleepace @phantomofslop Not necessarily. You can implicitly join on data you’re already storing. You only need explicit join tables for N:N joins. A graph is materializing implicit joins into actual edge objects.
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George
George@georgecurtiss·
almost all the data you deal with is a graph... so why are you using a relational database?
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George
George@georgecurtiss·
@fuzziphy @Asleepace @phantomofslop depends on the aggregations. also, we're yet to lose anyone's data. But I understand that's been a problem a lot in the past.
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Matt Thompson
Matt Thompson@fuzziphy·
@georgecurtiss @Asleepace @phantomofslop …If you want it to use more storage, be 10x-100x slower for aggregations, and lose your data. Graph DBs only make sense for deep depth traversal and path finding. Not relational, statistical, or time series.
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Matt Thompson
Matt Thompson@fuzziphy·
@zackslab @i2cjak Alternatively you can do low side sensing between low side switch and go direct to internal pga opamp, but you lose the falling ramp
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zack's lab
zack's lab@zackslab·
@fuzziphy @i2cjak ah that's a good point. i was going to naively rely on the CSA to reject the common mode, but moving it on the other side of L makes a lot more sense.
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zack's lab
zack's lab@zackslab·
okay rough block diagram, what am i missing? feel free to copy @i2cjak:
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zack's lab@zackslab

for the @i2cjak 48V dc/dc converter challenge: okay so covering 10mA to 10A current output is going to be more difficult than I thought now that I'm looking at behavior in simulation... approach: - 2 phases, fw will support phase shedding depending on iout. - iout >2A, both phases enabled, CCM - 2A > iout > 500mA, shed 1 phase, CCM - iout < 500mA, 1 phase with some kind of burst/skip scheme still need to figure out how to measure current across the whole range using some combination of sense Rs or DCR of the inductor or some combination.

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Matt Thompson
Matt Thompson@fuzziphy·
@zackslab @i2cjak Usually high side sensing is before the inductor. From L to SW node, common mode is 0V to Vout at every cycle with a bunch of noise. Last part yeah, just making sure your ADCs are triggered to be aligned to a quiet part of the switching cycle. See RM0440 page 973
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zack's lab
zack's lab@zackslab·
@fuzziphy @i2cjak shunts aside from the Rsense? (that's not supposed to be the L's DCR) yes i am looking at G474 datasheet now to see what it can handle from the analog blocks. that last part, you mean like a blanking window to not sample noise during the switch event?
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Keşfet

@embedrapp @ratatui_rs @orhundev @purusa0x6c @zackslab @i2cjak @ThrillaRilla369 @oelma__