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Search - "dma"
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Did you read about the new Digital Services Act and Digital Markets Act laws of the European Union, that will go in effect in 2022? Pretty neat stuff, more transparency, user rights and a tool against internet monopolies.
"Very big online plattforms" must submit reports on freedom of speech, abuse of human rights, manipulation of public opinion.
EU assigned scientists will gain access to trade secrets like google search or Amazon recommendation algorithm to analyze potential threats.
The EU can fine serial offenders 10 % of their yearly income. And break up companies that stiffle competition.
Internet companies like Facebook will not be permitted to share user data between their products like Instagram and WhatsApp.
There will be a unified ruleset on online advertisement. Each add must have the option to find out why this add is shown to the user.
Unlike the GDRP data protection rule the two acts will be valid at the Union level. So that there won't be any exceptions from single member states.
Let's hope this leads to a better Internet and not things like cookie pop ups 😄
Link to the EU DMA DSA page
> https://ec.europa.eu/digital-single...49 -
Just thought I'd share my current project: Taking an old ISA sound card I got off eBay and wiring it up to an Arduino to control its OPL3 synth from a MIDI keyboard. I have it mostly working now.
No intention to play audio samples, so I've not bothered with any of the DMA stuff - just MIDI (MPU-401 UART) and OPL3.
It has involved learning the pinout of the ISA bus connectors, figuring out which ones are actually used for this card, ignoring the standards a little (hello, amplifier chip that is wired up to the +12V line but which still happily works at +5V...)
Most of the wires going to it are for each bit of the 16-bit address and 8-bit data. Using a couple of shift registers for the address, and a universal shift register for the data. Wrote some fairly primitive ISA bus read/write code, but it was really slow. Eventually found out about SPI and re-wrote the code to use that and it became very fast. Had trouble with some timings, fixed those.
The card is an ISA Plug and Play card, meaning before I could use it I had to tell it what resources to use. Linux driver code and some reverse-engineering of the official Windows/DOS drivers got me past this stage.
Wired up IRQ 5 to an Arduino interrupt to deal with incoming MIDI data, with a routine that buffers it. Ran into trouble with the interrupt happening during I/O and needing to do some I/O inside the handler and had to set a flag to decide whether to disable/re-enable interrupts during I/O.
It looks like total chaos, but the various wires going across the breadboard are mainly to make it easier to deal with the 16-bit address and 8-bit data lines. The LEDs were initially used to check what addresses/data were being sent, but now only one of them is connected and indicates when the interrupt handler is executing.
There's still a lot to do after that though - MIDI and OPL3 are two completely different things so I had to write some code to manage the different "channels" of the OPL3 chip. I have it playing multiple notes at the same time but need to make it able to control the various settings over MIDI. Eventually I might add some physical controls to it and get a PCB made.
The fun part is, I only vaguely know what I'm doing with the electronics side of this. I didn't know what a "shift register" was before this project, nor anything about the workings of the ISA bus. I knew a bit about MIDI (both the protocol and generally how the MPU-401 UART works) along with the operation of a sound card from a driver/software perspective, but everything else is pretty new to me.
As a useful little extra, I made some "fake" components that I can build the software against on a PC, to run some tests before uploading it to the Arduino (mostly just prints out the addresses it is going to try and write to).46 -
Small test at school testing our knowledge of javascript and the p5js library.
One of the aims was to make a small rectangle slowly move across.
I lost one mark because I didn't define a y variable for the rectangle, even though the y never changes.
*sigh*5 -
I just learned about the glorious language called batsh. It compiles, to bat and bash.
Considering learning OCaml to contribute, this is the holy grail that will bind us all together.4 -
I teach app development over the summer, and the great thing about working with kids and having the last name Wayne is that I can very easily have them refer to me as Batman. I've never felt so cool.
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Funny thing the brain is.
TL;DR; being in the zone is nice. But there is another level of it and, fuck it, I'm loving it!!!
level 0: phased-out, relaxed state. Not focused on anything in particular. Just going with the flow
level 1: aware of the situation and of what's going on, not engaging too much
level 2: alert, ready to react. Constant concentration
level 3: THE ZONE. Time continuum is broken by concentration on the task in front of you - while working on it, time passes faster by magnitudes than when you're in any lower level. Surroundings and periphery do not exist. On;y the task currently in hand exists. Restroom breaks can wait.
level 4: body works on the task by itself. Any cognitive engagement with any of it will only make matters worse. The body knows it better, just let it do the work - let your consciousness sit back and relax, think about something nice. It's a sort of biological version of DMA (direct memory access), bypassing the CPU.
I've only reached level 4 several times, briefly and only while playing BeatSaber. The boxes are flying at me and hands just hit 'em the right way by themselves. Only after the hit, do I realise what my hands did and how cool it actually is. If I try to intentionally look at the boxed and aim for them, I mess it all up. And it's not like muscle memory - level 4 copes with any non-Camellia Expert level, regardless of whether have I played it in the past many times or just a few, several months ago.
I love that feeling!6 -
So happy about being about to convince management that we needed a large refactor, due to requirements change, and since the code architecture from the beginning had boundaries built before knowing all the requirements...
pulled the shame on us, this is a learning lesson card.. blah blah blah
Also explained we need to implement an RTOS, and make the system event driven... which then a stupid programmer said you mean interrupt driven ... and management lost their minds... ( bad memories of poorly executed interrupts in the past).... had to bring everyone back down to earth.. explained yes it’s interrupt driven, but interrupt driven properly unlike in the past (prior to me)... the fuck didn’t properly prioritize the interrupts and did WAYYY too much in the interrupts.
Explained we will be implementing interrupts along side DMA, and literally no message could be lost in normal execution.. and explained polling the old way along side no RTOS, Wastes power, CPU resources and throws timing off.
Same fucker spoke up and said how the fuck You supposed to do timing, all the timing will be further off... I said wrong, in this system .. unlike yours, this is discreet timing potential and accurate as fuck... unlike your round robin while loop of death.
Anyway they gave me 3 weeks.. and the system out performs, and is more power efficient than the older model.
The interrupting developer, now gives me way more respect...4 -
Fucken clock stretching.... seriously ... if you’re gonna clock stretch me for any more than 3ms (which is still pushing it) just fucken NACK me so I know your not ready god damn.... it’s fucken i2c .... stop with the application i2c bullshit... I just want to read the fucken registers stop abstracting it put it on a god damn DMA..
clock stretching is why we can’t have nice things lol12 -
Spent an hour trying to optimize some code but none of the stuff I was trying (rearranging/overlapping DMA transfers with other stuff for some ye olde concurrency) seemed to be doing anything.
Aaand obviously the stupid thing was set to autobuild Debug config on save but I was testing Release config. Sigh.1 -
Can anyone help me with this theory about microprocessor, cpu and computers in general?
( I used to love programming when during school days when it was just basic searching/sorting and oop. Even in college , when it advanced to language details , compilers and data structures, i was fine. But subjects like coa and microprocessors, which kind of explains the working of hardware behind the brain that is a computer is so difficult to understand for me 😭😭😭)
How a computer works? All i knew was that when a bulb gets connected to a battery via wires, some metal inside it starts glowing and we see light. No magics involved till now.
Then came the von Neumann architecture which says a computer consists of 4 things : i/o devices, system bus ,memory and cpu. I/0 and memory interact with system bus, which is controlled by cpu . Thus cpu controls everything and that's how computer works.
Wait, what?
Let's take an easy example of calc. i pressed 1+2= on keyboard, it showed me '1+2=' and then '3'. How the hell that hapenned ?
Then some video told me this : every key in your keyboard is connected to a multiplexer which gives a special "code" to the processer regarding the key press.
The "control unit" of cpu commands the ram to store every character until '=' is pressed (which is a kind of interrupt telling the cpu to start processing) . RAM is simply a bunch of storage circuits (which can store some 1s) along with another bunch of circuits which can retrieve these data.
Up till now, the control unit knows that memory has (for eg):
Value 1 stored as 0001 at some address 34A
Value + stored as 11001101 at some address 34B
Value 2 stored as 0010 at some Address 23B
On recieving code for '=' press, the "control unit" commands the "alu" unit of cpu to fectch data from memory , understand it and calculate the result(i e the "fetch, decode and execute" cycle)
Alu fetches the "codes" from the memory, which translates to ADD 34A,23B i.e add the data stored at addresses 34a , 23b. The alu retrieves values present at given addresses, passes them through its adder circuit and puts the result at some new address 21H.
The control unit then fetches this result from new address and via, system busses, sends this new value to display's memory loaded at some memory port 4044.
The display picks it up and instantly shows it.
My problems:
1. Is this all correct? Does this only happens?
2. Please expand this more.
How is this system bus, alu, cpu , working?
What are the registers, accumulators , flip flops in the memory?
What are the machine cycles?
What are instructions cycles , opcodes, instruction codes ?
Where does assembly language comes in?
How does cpu manipulates memory?
This data bus , control bus, what are they?
I have come across so many weird words i dont understand dma, interrupts , memory mapped i/o devices, etc. Somebody please explain.
Ps : am learning about the fucking 8085 microprocessor in class and i can't even relate to basic computer architecture. I had flunked the coa paper which i now realise why, coz its so confusing. :'''(14 -
I really don't want to dual boot windows and ubuntu, trust me,
but when I'm getting frame drops in chromium, while having a gtx1070ti, it's kinda hard to be a linux/ubuntu advocate and windows hater when every stackoverflow answer tells you to reinstall drivers
(╯°□°)╯︵ ┻━┻10 -
dammit ti why must your torture be limitless
> eZ80 has awesome DMA-like instruction that copies byte chunks based on registers and it's nigh-instant to copy 64k it's great
> TI has the opcode disabled outside a 4-byte chunk erroneously unincluded from all blacklists and access regulation
> can't bankswitch and keep registers, and can't write to anywhere but those 4 bytes in that bank
> no reusable code in target bank that i can use via mid-func bankswitch1 -
My first interaction with a computer was probably playing Parsec on an old TI-99/A we dug out of the attic. After that there were a lot of troubleshooting sessions with my dad on various computers trying to get some game up and running. I still remember the IRQ/DMA combination needed to get sound in Duke.
It really is no mystery why I ended up working with this stuff.