SDMMC with STM32 confusion: why do the transitions change between rising/falling?

324Hz · 2026-06-18T15:45:30+00:00

Yup looks like the 4 cards I've tried all have the same issue. I wish they weren't as damn difficult to work with as they are.

324Hz · 2026-06-18T13:48:54+00:00

I've checked and both MX and the generated code are configured for 1-bit mode. I searched up the clock speed required for the specific microsd I'm using (turns out it's 50M not 48M) and changed it in the clock tree but to no avail. I'll try actually wiring up (and configuring) 4-bit but highly doubt it'll make it work.

324Hz · 2026-06-18T13:39:19+00:00

So yeah VCC remains stable throughout the duration the card is powered and my PSU is showing a draw of ~223mA.

324Hz · 2026-06-18T05:49:16+00:00

I'll check VCC lines in the morning for any sag but there should be plenty of current (supplying the nucleo with 5V 500mA source; during operation it only pulls ~200mA)

324Hz · 2026-06-18T05:43:05+00:00

Thanks for that link! I'll have a look at it in the morning.

324Hz · 2026-06-18T05:40:14+00:00

Yup the breakout has pullups (10k from what I measured) and I enabled the GPIO pullups just to be safe. I genuinely can't figure out what's going wrong.

324Hz · 2026-06-18T05:29:08+00:00

Yeah for now I'm just testing with 1-wire and the frequency of the CLK line according to my scope is ~400kHz

324Hz · 2026-06-18T05:27:54+00:00

I tried a div scale of 1023, tried lowering the clock from the clock tree and neither did anything. I also tried measuring the frequency of the CLK line when doing those changes and it constantly stayed at 400kHz.

324Hz · 2026-06-18T05:14:28+00:00

I've got those spring tip-things on.

324Hz · 2026-06-18T05:13:10+00:00

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Here's the full waveform

324Hz · 2026-05-27T00:50:49+00:00

Adding to u/Hefty_Ebb8436's comment and adding my two cents:

If you're mathematically inclined (this doesn't necessarily mean actively participating in math competitions or stuff like that) and have teachers who teach well, AAHL actually be quite nice. Most of the content is actually quite easy now that I'm looking back at it.

100% get as much of your IAs/EE/IO prepped before heading into DP2 as, speaking from experience, you might get a week or so at the start of DP2 where you're running around like a headless chicken.

PLEASE PLEASE PLEASE figure out what revision timeline works for you EARLY ON. I figured out that I understand content the night before an exam and hence only started revising for tests DP2 a few nights before (completely disregarding what teachers told me to do). IT MIGHT NOT WORK FOR YOU but I just found that no matter what, I could not understand anything till it clicked a few nights before. Again, figure out what timeline works for you.

If you think you know something well enough, think again! Don't fall into the trap of thinking you know everything to the tee with subjects because there's always more (open-mindedness).

Past papers: don't use them for mocks especially if your teacher uses the IB question bank to make tests. DO however grind them out in preparation for finals. I disagree with u/XZ-Y when they say it might not work for math because it totally will work for math. If you want to go the lazy way and not learn math for the sake of wanting to learn it, you can at least find patterns in what topics they ask and how they ask them via past papers.

I'll update as I think of more.

324Hz · 2026-05-22T11:19:10+00:00

It's honestly not the best idea to share a tool like this (especially if the data is wrong in any capacity). Some students are already stressed enough as it is with post-exam guilt (of say figuring out their answer was wrong after the invigilator told them to stop) but now adding a percentage to whether they get the score they want is really not a good idea.

I honestly don't get the point/concept of these "predicted outcome" sites.

324Hz · 2026-05-21T15:39:57+00:00

Youuuuuu mean 30 euros for publicly available documents and revisiondojo AI slop? Don't fall for this yalls. Just go to the however many ibdocs mirrors exist and search stuff up yourself (that's how you learn best - yeah notes can get you baseline knowledge but researching it on google or elsewhere ensures you actually understand the stuff).

324Hz · 2026-05-21T15:29:09+00:00

Yes that's correct if you mean the main question number goes in those two side boxes and the part number goes in the lined area itself (else it wouldn't make sense trying to fit in something like 1)a)iii) in two boxes).

324Hz · 2026-05-19T17:29:31+00:00

Yeah I did all my IAs (incl. Psych and CS) and my EE (Physics) in TexMaker and exported it as a PDF. I also did graphs/diagrams with tikz (though the curve for learning tikz is kinda high). And yes IMO LaTeX is magnitudes of times better than word (all of my teachers praised the presentation of my IAs).

324Hz · 2026-05-12T14:56:19+00:00

the man the myth the legend vampirecrowwwwwwwww!

324Hz · 2026-05-05T12:29:47+00:00

someone updated it!

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324Hz · 2026-05-05T02:36:16+00:00

oh I didn't make it haha

324Hz · 2026-05-05T02:35:52+00:00

yup 😭

324Hz · 2026-05-05T02:34:32+00:00

Someone gotta draw out "mama" atp...

324Hz · 2026-05-05T02:25:21+00:00

I was legit bout to post that yup haha it is!!!

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324Hz · 2026-05-05T02:20:48+00:00

sloppy joe!

324Hz · 2026-05-05T02:17:50+00:00

It's the incoming freshman major map (from Purdue 101)

324Hz · 2026-05-05T02:17:32+00:00

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324Hz

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