Blotto Skorzany posted:

i had wondered for a while why the stack overflow checks in freertos never seemed to work (always reported that no overflow had occurred) and the mpu exception handler that i wrote always got called instead. i was poking around in the scheduler for other reasons and found this

code:

		//taskFIRST_CHECK_FOR_STACK_OVERFLOW();
		//taskSECOND_CHECK_FOR_STACK_OVERFLOW();

i guess that's why setting configCHECK_FOR_STACK_OVERFLOW to the appropriate value didn't do anything. i'll have to check git to see whether a coworker did this or if the main distribution had this bug at the time we grabbed it.

Bloody posted:

the answer is probably extremely platform-specific and i dont know arms well enough off the top of my head to answer so instead i am ing

Luigi Thirty posted:

wasn't this basically how the first practical telegraphs worked? a guy in Paris pushing a lever on a hydraulic pipe that signified a letter?

Mr Dog posted:

the plan was

1. design some poo poo
2. hire some poor bastard (me) to actually make it work

tbf it could be a lot worse (STM8 isn't ARM but at least it isn't loving Microchip and it's a lot better than AVR because it has a flat 16-bit address space) but all of this poo poo is low-volume and yet the bom cost is supposedly super important and yet there's all sorts of useless and very expensive components all over these boards. like every single one of them ships with a big chunky debug connector as opposed to idk just using pogos like a sane person. who the hell ships populated debug connectors to end users i mean wtf people. or the aforementioned 1.5F supercap which i don't even know what the gently caress it's doing there but it can't be cheap

JawnV6 posted:

how do i test freeRTOS tick rollover

0xffffffffms is ~49 days, I need some way to start it at 0xfffff000. lot of internal structure means I can't just jam that value in at reset

internally, there is literally nothing done to handle it. all the comparison math is ovf-safe, im not smart enough to make that same guarantee for my stuff

Apocadall posted:

2nd year of computer engineering school down, realizing i like working at bit level, just feels more real, bought an oscilloscope, a rigol ds1054z because it seemed best bang for buck and with the 100MHz hack it should be all i need for a large amount of things for a while

having to write my own usb protocol and enumeration or aprs stuff has felt really rewarding because these things no longer just seem like magic, but that i'm actually starting to understand how this poo poo all really works, and not in a hand-wavy abstracted way

next semester going to take classes on embedded systems and processor and memory architecture

one question i do have, is where do i look for jobs in this kind of stuff? i know i'll need to leave maine because there isn't poo poo here for anything like that except a TI and Fairchild in Portland, i think there might be one more but it got bought out recently

atomicthumbs posted:

gonadic io posted:

dumb noob question

if i only have a 24V battery, and i use some DC/DC regulator to get it to 3.3

can i have

pre:

+24V ----- motor --|
       |           |
     DC/DC         |
       | (+3.3V)   |
     arduino       |
       |           |
 +0v --------------|

i.e. i don't need to protect the arduino from the ground rail, 0 is 0? the motor will have a rectifier diode to prevent kickback.

Phobeste posted:

never forget this universal truth: every graphical design "helper" for embedded work is a pile of trash. on the particularly good ones they'll support ~90% of the chips capabilities and if you're lucky you'll be within that 90%, and it'll only be a mostly tedious and incredibly painful process that doesn't get you much over just configuring it yourself in code. on bad ones that only support ~80% or if your task requires something outside the supported set you're hosed because they're a) never set up to work in a modern programming environment with source control and automatic builders and b) often want to control everything and are tough to impossible to integrate your own code into.

i mean if it's for loving around sure it's $10, but psoc creator in particular is a callback to the bad old pre-cortex days of every arch requiring its own godawful vendor-"supported" toolchain. poster otto skorzeny used to rant all the time about this one in particular too