Luke Wren @wren6991@types.pl @wren6991 Twitter profile

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@tihinker

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@MarcParlange

@vincent09040904

Luke Wren @[email protected]

@wren6991

1 month

Over 200 MiB of cache. If yall weren't so bad at programming we wouldn't even need SDRAM

TechPowerUp

@TechPowerUp

1 month

AMD Ryzen 9 9950X3D and 9900X3D to Feature 3D V-cache on Both CCD Chiplets

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Luke Wren @[email protected]

@wren6991

2 months

I finally have a legitimate use case for one of these awful HDMI to screw terminal adapters, I'm so excited

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Luke Wren @[email protected]

@wren6991

3 months

Didn't expect this level of sass from the libgcc soft float implementation

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Luke Wren @[email protected]

@wren6991

3 years

I think there is a strong argument that a buffer should be called an OT gate 🤔

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Luke Wren @[email protected]

@wren6991

4 years

I knew many oscilloscopes run Windows, but it really sank in today when I saw a coworker in the lab running a Webex conference call on one of the scopes. They were live-sharing the oscilloscope screen, whilst making changes to the circuit's input and discussing on the call

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@wren6991

2 years

When I run `ffmpeg --help` I distinctly feel my computer take a deep breath before it starts to explain

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Luke Wren @[email protected]

@wren6991

3 years

Factorio players are optimising their belt balancers by reducing belt balancing to SAT and feeding to a SAT solver. Fucking incredible

GitHub - R-O-C-K-E-T/Factorio-SAT: Enhancing the Factorio experience with SAT solvers

Enhancing the Factorio experience with SAT solvers - R-O-C-K-E-T/Factorio-SAT

github.com

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Luke Wren @[email protected]

@wren6991

1 year

I'm a big fan of high-level languages, such as x86 assembly

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Luke Wren @[email protected]

@wren6991

2 years

Yet again there is discourse about debuggers vs printf, but why don't more people use a waveform viewer to debug their software? Works for me

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Luke Wren @[email protected]

@wren6991

4 years

Did some soldering yesterday

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Luke Wren @[email protected]

@wren6991

2 years

Wow, apparently Factorio implements nonblocking autosave by literally calling fork() and then saving from the forked memory in the background. Game chugs for a bit because of all the copy-on-write penalties, but it avoids pausing the game for an autosave

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Luke Wren @[email protected]

@wren6991

2 months

PCB twisted pair

天球儀

@hanai_y

2 months

有効なのは分からんでもないけどもやもやするｗ

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Luke Wren @[email protected]

@wren6991

3 months

Datasheet is live: Hopefully we kept you all guessing on what the "3" stands for in RP235x! Cortex-M processors are clearly best-in-class, but I hope you have fun playing with my core too.

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Luke Wren @[email protected]

@wren6991

5 years

Verilog is a wonderful language because you find things like this in the standard (1364-2005 5.4.2) How can you write something like this and not go "wait, go back, we fucked up"

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Luke Wren @[email protected]

@wren6991

4 years

Good morning! Feel like bitbanging some DVI from my new microcontroller.

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Luke Wren @[email protected]

@wren6991

1 year

PCB design is my passion

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@wren6991

2 months

@jwt0625 I assume it is not rated for 13 amps at 240 VAC

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@wren6991

2 years

This whole slide deck is funny and informative, but this slide in particular I think needs to be printed out on my wall

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Luke Wren @[email protected]

@wren6991

3 years

I wonder how many processors there are in an "empty" modern motherboard? At least one of them can run a USB + FS stack. How many of them are 8051s?

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Luke Wren @[email protected]

@wren6991

3 years

The trolley problem has been solved!

B作

@Btoretsukuru

3 years

『トロッコ問題』で全員助かる方法こんな答えはどうかな？ #鉄道模型 #N ゲージ

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Luke Wren @[email protected]

@wren6991

2 months

Someone is already running RISC-V NOMMU Linux on RP2350. Knew I was going to get sniped on that one.

GitHub - Mr-Bossman/pi-pico2-linux: RISC-V linux on the raspberry pi pico 2

RISC-V linux on the raspberry pi pico 2. Contribute to Mr-Bossman/pi-pico2-linux development by creating an account on GitHub.

github.com

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Luke Wren @[email protected]

@wren6991

2 years

Really wish synthesis tools would stop warning you when they perform basic optimisations

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@wren6991

5 years

Who called it "jet lag" and not "clock domain crossing"

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@wren6991

3 years

I did a thing

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Luke Wren @[email protected]

@wren6991

3 years

Periodically think about my first year dynamics + structures supervisor who used Matlab for photo editing Just loaded it in as a big matrix, did some operations to adjust brightness and contrast, saved back out as a JPG Definitely a Type Of Guy

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Luke Wren @[email protected]

@wren6991

4 years

Tired: profiling Wired: toggle a GPIO on function entry and exit, measure the duty cycle

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Luke Wren @[email protected]

@wren6991

2 months

Weird how IEEE 754 only parameterises the number of exponent and significand bits. We should be allowed to have more sign bits too.

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Luke Wren @[email protected]

@wren6991

5 months

Upcoming Arm ThinkPad replaces PrintScreen with a copilot key. Replacing a useful key with a physical ad for LLM slop is a way to ensure I won't buy your product Hopefully when this bubble bursts we all go back to selling monkey JPEGs. It was an honest living, comparatively

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Luke Wren @[email protected]

@wren6991

4 years

What's your favourite Python 3 operator? Mine is the w i d e operator

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Luke Wren @[email protected]

@wren6991

2 years

Would love to have the confidence of the person who pasted an entire C header into an IEEE standard and labelled it as normative

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Luke Wren @[email protected]

@wren6991

5 years

Multilayer boards are so beautiful before you flood the planes!

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Luke Wren @[email protected]

@wren6991

3 months

I just published the v1.0 release of Hazard3, my 3-stage RISC-V core. There aren't many new features, but there's a lot of cleanup and maintenance work that will make it a better platform for development going forward. Read the release notes here:

Release v1.0 · Wren6991/Hazard3

This is the first stable release of Hazard3. It fixes the following errata from the v1.0-rc2 release candidate: PMPCFG fields R and X are transposed: fixed by 7d37029 mstatus.mie is not ignored in...

github.com

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Luke Wren @[email protected]

@wren6991

1 year

If I could snap my fingers I would make the terms "Von Neumann architecture" and "Harvard architecture" disappear from every undergraduate course on computer architecture, until we decide whether they describe an architectural or microarchitectural decision

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@wren6991

5 months

LPDDR5X-8533? My dude that is not synchronous DRAM, that is radio frequency DRAM

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@wren6991

2 years

Using ":-)" when emailing older coworkers is a form of code switching

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Luke Wren @[email protected]

@wren6991

4 years

Don't recall who asked about 800x480p60 but yes it seems to work. Not sure how that image got there

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Luke Wren @[email protected]

@wren6991

5 years

Actual line of C encountered in the wild: ((void (*)())0x10000101)(); It has everything: void, parentheses, 1s and 0s. It's like the e^(i pi) + 1 of C programming

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Luke Wren @[email protected]

@wren6991

2 years

At last... the third boolean

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@wren6991

3 months

The RP2350 ROM source being out means I can share two of my favourite functions: unpacking `bl` and `movw` immediates using RV32IBZbkb. It took a lot of squinting to get these right, I wonder if anyone can knock another cycle off? (Also it's a shame pack/packh aren't in Zbb!)

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Luke Wren @[email protected]

@wren6991

3 years

Full shareware DOOM with multiplayer, 264 kB of RAM and 2 MB of flash! Looking forward to seeing the writeup 😃

graham sanderson

@kilograham5

3 years

Happy Pi Day! #RP2040 #Doom is here with the FULL DOS game experience 320x200 VGA, 9 channel music, sound effects, 1-4 players (I2C), USB keyboard, saved games, cheats, demos, all cut/end screens Fits all 9 shareware levels on 2M @RaspberryPi Pico! 1/4

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@wren6991

2 years

"Multi function gate" (squints) that is literally just a mux

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Luke Wren @[email protected]

@wren6991

3 years

CPU ideas: - Bit-serial Itanium - Out of order superscalar 6502 (65OoO2) - 16-bit RISC-V ISA variant (RV16I) - Microcontroller with Cell SPEs - Jazelle DBX, but for Lua bytecode on RISC-V Free to a good home

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@wren6991

2 years

Designing a 16-bit serial processor for Tiny Tapeout 2. It jiggles its registers to save area. Very serious logic design.

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Luke Wren @[email protected]

@wren6991

4 years

Thinking about the 86 people who bought this off Amazon

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@wren6991

3 years

Example of a 16-16 balancer found by the solver, shorter than the previous best known by 1 tile:

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Luke Wren @[email protected]

@wren6991

3 years

Want to make a carrier board for @arturo182 's RP2040 Stamp that fits into an AliExpress Gameboy. Minimal circuitry for the first revision. I'm going with the meme solution of using the 2.5mm TRS jack as a debug connector so I don't have to open the case to debug it

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Luke Wren @[email protected]

@wren6991

3 years

Writing some good code today

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@wren6991

3 years

@lindsey HW eng: so we have some CPUs with caches Verification eng: gotcha HWE: they implement atomic accesses, so sw can build locks etc VE: um HWE: every trillion cycles or so, a core gets starved VE: (hands shaking, opening whisky) HWE: so we randomly perturb state and retry the access

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Luke Wren @[email protected]

@wren6991

3 years

Cat (and I cannot stress this enough) Printer

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@wren6991

4 years

This is the most exciting white text on a black background I have seen in a long time

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@wren6991

2 years

When academics use words like "A Primer" it means you're about to get the insides of your brain rearranged

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Luke Wren @[email protected]

@wren6991

3 months

New version of PicoDVI. Most of the Arm assembly in libsprite and libdvi is now ported to RISC-V. Adds support for the RP2350 TMDS encoders.

GitHub - Wren6991/PicoDVI: Bitbanged DVI on the RP2040 Microcontroller

Bitbanged DVI on the RP2040 Microcontroller. Contribute to Wren6991/PicoDVI development by creating an account on GitHub.

github.com

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Luke Wren @[email protected]

@wren6991

4 years

The parts always look smaller on the schematic!

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@wren6991

6 years

It's crazy to me that formal solvers can write RISC-V programs without any innate knowledge of the instruction set. Just attach a memory, tell it to assume PC never leaves that memory, and it will write all programs with that property, to test my assertions

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Luke Wren @[email protected]

@wren6991

4 years

I am enjoying the doom source

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@wren6991

5 years

Product idea: a multimeter with headphones, so you can beep out a circuit without pissing off everyone in the office

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Luke Wren @[email protected]

@wren6991

4 years

Time for my annual reading of the J1 Forth CPU paper. It's just so pretty! The way the core, the architecture and the language tile together. I still haven't clocked how he bootstrapped the toolchain so quickly, starting to see why Forth is a cult classic

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Luke Wren @[email protected]

@wren6991

2 years

posted without context

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@wren6991

3 years

Debugger acknowledges that my core is, in fact, a 32-bit RISC-V processor 🥳 they grow up so fast! (pic: openocd happily bitbanging JTAG in my CXXRTL sim through a TCP socket)

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Luke Wren @[email protected]

@wren6991

3 years

I don't know who needs to hear this, but please stop writing string parsing in Verilog

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Luke Wren @[email protected]

@wren6991

1 year

Also systems programming languages, such as udev rules

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Luke Wren @[email protected]

@wren6991

2 years

A game I like to call "Factorio or FPGA floorplan" (source: )

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@wren6991

4 years

Seen some people mention the lack of DAC on RP2040, but you can DMA to the core supply voltage select register, so idk what they are complaining about

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@wren6991

4 years

Electronics diagrams that look like shitposts

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@wren6991

3 years

SDRAM easter eggs! 2-row tRC violation: copy entire rows of data within a subarray 3-row activation: compute bitwise functions Now, 4-row activation: generate true random numbers at Gb/s speeds Wonder what we unlock by activating 5 rows at once, maybe hidden RGB LEDs?

SAFARI Research Group

@SAFARI_ETH_CMU

3 years

Tomorrow Ataberk Olgun will present "QUAC-TRNG: High-Throughput True Random Number Generation Using Quadruple Row Activation in Commodity DRAM Chips" @ISCAConfOrg Wed June 16 Session 11A 1:15 pm EDT Paper: Slides(pdf): @_onurmutlu_

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@wren6991

3 years

This is the SoC I want to build on ULX3S over Christmas to prove out my global atomics, and maybe port some software. Christmas SoC. It's an odd bus architecture, but something I can cobble together without designing any significant new components, like uhhh coherent caches

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@wren6991

4 years

Is it a good idea? Absolutely not. But did I at least execute it well? Again, no

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@wren6991

4 years

@_Ninji @alt_kia Hardware XML parser implementations are a thing! I see papers popping up on r/FPGA every now and then with ominous references to "real-time XML parsing"

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@wren6991

5 years

Spent a lot of time wondering which is the greater evil out of the I2C standard, and I2C implementations. Overjoyed to say I have found a new contender: flow charts from I2C hardware documentation You can't have a decision box where the only option is "Y"???

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Luke Wren @[email protected]

@wren6991

2 years

Out of curiosity, had a look at driving RP2040's pads open-drain for DVI, since it's closer to the current sink intended for TMDS. Left is the existing push-pull, right is open-drain, both at 252 Mbps (480p 60 Hz). Yeah that's a no 😅

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Luke Wren @[email protected]

@wren6991

1 year

Tonight I realised that I had left the RISCBoy repo in a broken state, so I fixed that up. Some of these demos are moving a lot of pixels for 36 MHz! Maybe I need to go back and revisit this, I'm sure there are a lot of things I would do differently today.

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Luke Wren @[email protected]

@wren6991

3 years

If you struggle to remember whether UARTs are MSB-first or LSB-first, here's a handy tip to figure it out: implement a UART, and the correct bit order is the opposite to what you implemented

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Luke Wren @[email protected]

@wren6991

11 months

Cortex-M3 Cortex-M3 Pro Cortex-M3 Max Cortex-M3 Ultra

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@wren6991

3 years

"standard" UART rates should be destroyed, just use divisions/multiples of 1 Mbaud you filthy animals

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Luke Wren @[email protected]

@wren6991

4 years

That's now two people who have hooked up an HDMI connector directly to a breadboard and had it work flawlessly. Pump this shit straight into my veins

@[email protected] vriska

@leo60228

4 years

@wren6991

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@wren6991

4 years

The curse of looking at random pieces of hardware and thinking "you could fit an FPGA in there"

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@wren6991

4 years

Sudden urge to build a 2-stage RV32I. There is just something pleasing about 2-stages

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@wren6991

2 years

Yesterday I got a lint for "redundant subexpressions" my dude that is literally your job, you are a compiler

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@wren6991

7 months

TIL the "D" in D-PHY doesn't stand for anything, it's a Roman numeral

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@wren6991

5 years

Best thing I've seen on the orange website so far

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@wren6991

2 months

First time in Japan. It's true, these power lines do be hitting different

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@wren6991

4 years

Hey this looks pretty good in colour!

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@wren6991

2 years

I posted this as a joke, but there is truth in it. More than once I have had a processor pass RISC-V ISA compliance but fail to execute a nontrivial printf format. I have never seen the opposite.

Luke Wren @[email protected]

@wren6991

3 years

When your processor runs `printf("%f\n", 1.23f);` with soft float it's ready to ship

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@wren6991

4 years

I saw from @arturo182 that they make a 100x100mm version of this hot plate (946-1010), which is just right for the boards I make, so I went ahead and ordered one. It goes down to 50°C, so I figure when I'm not soldering I can use it to keep my tea warm. Seems perfectly safe

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@wren6991

4 years

Good sign if you can get to blinky without reading the documentation! What a lovely board

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@wren6991

3 years

Haha PLL goes boingggg

金魚

@twi_kingyo

3 years

できたｗ　といってもGPSモジュールが出す10MHz信号（CH2）とVCTCXOの信号（CH3）を位相比較してVCに与えているだけだが... 　ループフィルタの帯域落としすぎてロックが遅いｗ

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@wren6991

2 years

Thinking again about this Super Metroid walkthrough where the text is perfectly justified through word choice alone

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@wren6991

4 years

@The6P4C I am so ready to spend an hour drawing different types of mechanical keyboard switch on the whiteboard. Not my fault they can't scope a question

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@wren6991

2 years

First post on cohost: "Designing a terrible processor in 6 days"

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@wren6991

4 years

@arturo182 you can see why we went to 40nm, the first ones were huge

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Luke Wren @[email protected]

@wren6991

2 years

General-purpose CPU implemented with RP2040 DMA control lists:

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@wren6991

4 years

Had great fun talking to @AlessandroDevs and @fixxxxxxer yesterday! Here is one of the demos we shared: VGA + I2S + SD card media player running at 48 MHz thanks to @kilograham5

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Luke Wren @[email protected]

@wren6991

4 years

Wait, that's a UART

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Luke Wren @[email protected]

@wren6991

3 years

Take a drink every time the Verilog standard doesn't specify fundamental behaviour of some operator

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Luke Wren @[email protected]

@wren6991

3 years

@the6p4c 2 types of hardware engineer

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@wren6991

2 months

-mcpu=rp2350-hazard3 is getting added to LLVM 🥳 (rp2350- because it's for that specific configuration)

[RISCV] Add Hazard3 Core as taped out for RP2350 by lenary · Pull Request #102452 · llvm/llvm-pro...

Luke Wren's Hazard3 is a configurable, open-source 32-bit RISC-V core. The core's source code and docs are available on github: https://github.com/wren6991/hazard3 This is the RISC-...

github.com

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@wren6991

2 years

*hits bong* what if the debug probe enumerated as a USB-ethernet device and just ran a debug translator and gdb server on-probe

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@wren6991

5 years

Making a thing I needed

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