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Comment by MegaDeKay | Hacker News Reader

The PIO's really are the star of the RP2040 show, giving it a capability that competing chips like the ESP32 can't match. They are appearing all over the place in the console hacking space for this reason. Lower power consumption in steep modes for battery-backed applications would be a welcome addition in any V2 version though.

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Things like battery life will probably improve with experience, I was talking to a silicon guy about the RP2040 and they said it's pretty characteristic of a first generation design. The digital logic that can be validated on an FPGA is fine for the most part, but the analog elements are much more difficult to fine tune, hence the poor power consumption, poor ADCs, and lack of internal DACs or opamps in the RP2040, and why the Pico Ws radio is a separate off-the-shelf part rather than fully integrated like it is on the ESP32.

Analog is large area and expensive in general so sticking to good digital and passable analog is a very good strategy to keep costs down.

Modern Microcontrollers focus on analog because modern microprocessors start at like $5, maybe even cheaper.

If you need digital girth, don't mess with lol 264kB RP2040 systems. Just buy $3 of DDR3L RAM (aka: 128MB) and run Linux for goodness sake.

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Even ESP32 is a glorified Bluetooth/Wifi chip first and everything secondary. You have to have a niche at this price point to be competitive.

RP2040's niche is the 264kB of SRAM, but not much else. It needs a bunch of external parts before it can become a reasonable solution as well, so its not really cost optimized IMO.

You can't run Linux on DRAM. You need a CPU.

You can't run anything on an RP2040. There's no Flash or code space.

RP2040 sits at an awkward placement. It requires external parts, but low end SPI parts and not the nicer proper RAM like DDR3L or the like.

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My point is that if you have a design that fundamentally requires external parts like the RP2040, the accurate comparison is against MPUs. Chips that are specifically designed to work with powerful and cost effective external components.

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Analog-focused designs like ATMega, ESP32 or STM32 comfortably do things that the real computers or MPUs cannot do. Like read a voltage, work with OpAMPs or other analog stuff that cannot fit on a proper Linux computer chip like SAM9x60D1G. And to do so without any external parts, so that you have the simplest design possible.

Glad you mentioned Microchip. The PIC32MK family is MIPS architecture microcontroller, with hardware floating point unit, running at 120 MHz, with a whole slew of peripherals, like 10 MHz unity-gain op-amp, D/A converter, lots of flexibility in mapping peripherals to pins, fast A/D, DMA, etc..

https://www.microchip.com/en-us/products/microcontrollers-an...

ESP32 chips also need external SPI Flash, and many STM32 have little flash and QuadSPI with execute from external flash capabilities, so I don't see this as a specificity of RP2040.

Some ESP32 chips have in-package flash, e.g. ESP32-C6FH4.

Turns out you can actually run quite a lot with dual core CPU clocked at 250MHz. You can also use part of the flash as file system, but that's not quite as straight forward.

Many devices run entirely from RAM which is completely viable with the ROM bootloader/SWD.

Though it's a continuing puzzle to me why ESPs have worse ADCs than the rp2040, given their relative maturity. (Neither is particularly good, mind you, but I'm generally ok with the rp for my toy applications.)

Speaking of relative maturity, I just had a heap corruption debug for a few days. Imagine my surprise when fixing the issue involved switching from the default ESP32 BLE library to the NimBLE library...

I have been having an intermittent issue as well, but only when using BLE, so I was suspecting the Espressive drivers. I was wondering if it would be worth switching over to NimBLE, so thanks for that tip, I'll try it out and see if the problem goes away. Luckily, it's a very low priority.

If you read through errata and compare editions of the tech docs, it becomes apparent ESP32 has a history of silicon problems with its ADC's - through a few generations of their chips. In some models they removed huge swaths of related functionality from their documentation because it was bugged.

They're slowly getting better but analog is hard and I suspect they haven't prioritized it as much, historically.

he said?

I was thinking about this. I think there is a trend in English to use they even when the gender is known to indicate a kind of distance from that person. E.g. my guess about the parent poster is that they (he or she in this case, a different usage) may not be very close to the "silicon guy"

I don't think this is the case. Isn't it that "guy" is essentially gender neutral in this context? In the same way you can reasonably say "hi guys" to greet people of any gender.

"Silicon person", "silicon gal" etc would be weirder phrasing. "Silicon specialist" maybe but I don't personally think any of this merits discussion.

Maybe it's used neutrally in greetings (e.g. "Hi guys,") but when referring to someone specific, if you say they're a guy, it will generally be assumed that person is a man.

There's no maybe about it. And it goes beyond greetings. But I do agree it was non-sensical here

You're right, people do use it neutrally in greetings, not just maybe. And in more than greetings, more as a general form of address. More specifically, I would say that when not used to address multiple people in the second person (i.e. when saying "you guys"), then the word "guy" implies that the referent is male.

Except for idioms like "I've got a guy" where you just mean you've got someone in mind. And that's where I was coming from with "silicon guy" or "hardware guy", "software guy" etc. Just as generic terms for your goto person in those fields, no gender implied.

I hadn't heard anyone use the word "guy" like that before now, and didn't know the word was used like that, so I wasn't thinking of those cases. If you said "I've got a guy" or "software guy" I'd assume you meant you had someone in mind who's a guy, i.e., male. I believe you, though. This might be something that differs regionally.

This confuse us foreigners trying to use the English language even more than it must confuse regular english speakers.

Not only did you (you guys, y'all, plural you, whatever...) mix up ye with you, using only the object form, but also started using it for thou and thee. Also, it was thy/thine not yours in the singular form.

I suggest you "fix" your language by reintroducing these words, they (plural they) are not completely lost yet (ref: dialects and the Bible).

https://langeek.co/en/grammar/course/8/archaic-pronouns#revi...

I'll give it a shot, but what about the grammatical singular agreement of the rest of the sentence? Should I leave my second-person verbs in the plural, as in you do, you have, or modify them, as in thou dost, thou hast?

https://en.wiktionary.org/wiki/-est#Middle_English

I guess you're basically asking me to speak dialectical Yorkshire.

I agree with this take. How the word "they" was used in the sentence implies a kind of "anonymous other", especially when they're a part of a group like a company. It could have been any member of that group, male or female. And there's a lack of individuality or familiarity, it doesn't matter so much the exact person.

Some time around the year 1500, English speakers stopped addressing each other as "thee" in favor of the plural form "you". The singular "thee" is intimate and informal, but might be considered rude in the wrong context. So using the more polite plural form "you" in all contexts is a safer option.

Many young people seem to use the gender-neutral "they" rather than "he" or "she", even when the gender is known and is unambiguous. This may turn out to be a fad, or it may be a similar generational shift in the language.

What I find quite interesting is in the northern irish dialect, plural you is quite uncommon, usually plural you becomes yous or yousins, because irish has seperate words for singular and plural you

I wonder if the 20th century NYC dialect had "yous" from the wave of irish immigrants. As in "Yous guys ova hee". (Speaking as a native new yorker who doesn't hear this dialect much anymore except for maybe at a mechanic in, say, south brooklyn)

> Many young people seem to use the gender-neutral "they" rather than "he" or "she", even when the gender is known and is unambiguous. This may turn out to be a fad, or it may be a similar generational shift in the language.

I don't know if it's generational, but on the internet it's less clear what someone's gender is, and assumptions have a decent chance of being wrong. The result is that I typically try my best to default to "they" for anyone who hasn't asked me to use different pronouns.

The vast majority of real, commercial MCUs do not have WiFi in-package. The ESP32 is unique in this regard and is one of its only redeeming features.

I would rather buy the RP2040 and the NRF7001/NRF7002 for the same or less total cost and have a substantially better wireless solution (5.4GHz WiFi 6).

The most annoying part about the PIO is that there are only two of them (though with 4 sub-units each), they only have space for 32 instructions, and they don't have an external clock input.

They are great for implementing very basic peripherals, but more than once I've started to implement something more complex just to realize it would be unacceptably slow and run out of space. If they were to beef them up just a little, they could easily replace the more trivial FPGA applications.

Add a $2.80 ICE40 with built-in NVM and your problems are solved.

Considering the RP2040 is only $0.70, not exactly an attractive option.

If an RP2040 doesn't fit the task because it has a pitiful amount of IO, you're now into using two anyway. Two chips, two SPI flashes, two crystals - likely more than the FPGA.

If it matters for the task, that FPGA will be able to achieve nanosecond-order IO/clock-to-clock skew times - PIO is painfully bad at this (and is executed serially.)

If the task will fit FlexIO's restrictions, the NXP IMXRT1011 at $1.70 blows away the $0.70 RP2040 in basically every metric.

Availability is the star of the show for me. One IC, long product lifetime, always in stock, after the shitshow that was 2021/2022 I'm not going to bother trying to shave a few cents to compromise this again.

The RP2040 was only available during the last component shortage, since it was a newly released design, not yet implemented in many products.

The IC will be unobtainable in the next shortage, too.

I mean, don't you remember the shortage before where even capacitors were only hardly available?

Don't worry. No one is bothering with it outside of the hobbist market because it needs an external SPI flash chip, which one cannot protect by programming fuses. Your code is left unprotected, the Chinese can easily clone your product and put millions of units on the market. The ESP chips are a better pick even with all the bugs involved. It's quite typical of the Chinese manufacturers to have like 30 models of some product and release a few new ones every few years. The ESP is no different.

External SPI flash can be encrypted on-the-fly with most real commercial MCUs - the issue is that this was not designed to be a commercial MCU for use in products.

Relative to other offerings, it's pretty nice (not a fan of ESP32 Xtensa or their new RV32 offerings - ARM chips are so much better) as a DIY/hobbyist/open source chip.

Ditto for robotics. 8 PIO units are enough to read and log four quadrature encoders at practically no interrupt cost, so it's possible to build a perfectly performant closed loop controller in something as slow as Micropython.

You don't even need the 8 :), 4 quadrature inputs will fit on one PIO block.

Some lovely person got a quadrature decoder into 24 instructions, so you can potentially still do something useful on the same PIO block if you only need one or two quadrature encoders.

I mean yeah one block is 8 units right? Two pins per encoder which both need a unit each.

4 units per block, 2 blocks per RP2040.

Many, many cheap MCUs have peripherals that can decode quadrature in hardware. E.g, PCNT on ESP32, timer modes on STM32 etc. Might as well use PIO to implement I2C or UART :)

> Might as well use PIO to implement I2C or UART :)

PIO actually came in handy for me when interfacing with an x-ray sensor which had 12 or 14 bits long UART data frame- not many micros have such a flexibility in their UART peripherals.

> PCNT on ESP32

Damn TIL, never heard of that. I'll have to try it, thanks!

It’s also possible to build a perfectly performant closed loop controller with micropython on an STM32

Comparing ESP32 to RP2040 is like comparing oranges to apples.

If you need a lot of IO - you're probably not looking at ESP32. It's just cheap and has WiFi builtin.

There are many options for other MCUs, that compare favorably to with RP2040... though majority aren't for the hobbyist market.

> There are many options for other MCUs, that compare favorably to with RP2040

That's pretty interesting, could you list some?

The STM32 F0/G0/C0 lines come to mind. More I/O, more peripherals and built-in flash.

For hobbyist levels, buying 1-10 pcs they are comparable in price to an RP2040 + SPI flash. However at volume pricing, the STM32 MCU's can be cheaper than just the RP2040 itself. I do think Raspberry Pi needs to figure out volume pricing if they want to be competitive for anything that's not just hobbyists.

rp2040 is 64cents @ 1000qty, thats a good price, compatible winbond 16mbit flash is 12cents.

You need to go up way above a dollar to get comparable specs, given the unique nature of rp2040, two cores with fairly high clock, 264kb sram, pio.

The only thing i dont like about rp2040 is the package, not hobbyist home soldering friendly for custom board designs.

  > not hobbyist home soldering friendly for custom board designs

I assume by home soldering friendly, you mean too small. I'll make a case for why this isn't a bad thing...

If it's difficult to solder a QFN package, then it will be equally difficult to solder the passives and flash it requires. Its price, availability, and good documentation make up for the package by creating an ecosystem of cheap boards hobbyists can use instead.

For example, I designed a keyboard around the Solder Party RP2040 Stamp (https://www.solder.party/docs/rp2040-stamp/). It integrated all the difficult components in a package that fit between the arrow keys and delete key.

> If it's difficult to solder a QFN package, then it will be equally difficult to solder the passives and flash it requires.

Compatible winbond flash is available in sop-8 package which are very easy to solder. 1206 and 0805 are not hard to solder. Nobody is forcing you to use 0201 and 0402.

Sop, tssop or even LQFP-64 are still quite fine for hobbyists. Those can be soldered & most importantly examined quite easily.

Yes, there are various RP2040 boards that can be bought for as low as 2-3dollars a piece which makes the QFN package less of an issue.

If I need to design my own board, I would almost certainly likely use something else unless I need PIO or some other inherent quality of rp2040.

> The only thing i dont like about rp2040 is the package, not hobbyist home soldering friendly for custom board designs.

- Use home SMT reflow solutions like toaster ovens or hot sand in frying pans; or

- As the other reply suggested, use 'breakout boards' to turn the RP2040 into a through hole part; or

- Use SMT assembly services, which are getting cheaper all the time

It's not just a problem with the rp2040 - loads of modern parts have very fine pitches and/or hidden pads, gotta find a way to work with them or stick to aging out, larger parts and miss out on things like PIO.

At $1.70 (CN sources) you can obtain a 600MHz NXP IMXRT1011 with an M7 core + FlexIO and a dozen more peripherals of all types.

Not sure about favorably, but if it's PIO you're after, there is TI's Sitara family with their PRU. afaics, more functionality for a higher price.

But then you have to deal with TI’s garbage called CCStudio

Which is sad, because on paper the TI Sitara MCUs are unbeatable for peripherals and cost.

TI, if you're reading this:

- Give me standard ARM SWD facilities / CoreSight

- Give me an accurate SVD

- Give me a 10,000 page document detailing the register maps and behavior of all peripherals

- Get out of my way

And nobody else will be able to compete. (Who has USB SS/PCIE/N GMACs in one product? PRU?)

Where can I learn more about how they are used in console hacking? This sounds very interesting

One use case is related to the Nintendo Switch, as mentioned in another post.

E.g. see https://github.com/Ansem-SoD/Picofly.

Here you go. There might be more but these are all I can think of off the top of my head.

Nintendo Switch modchip - PicoFly: https://github.com/rehius/usk. That is the OG source of the firmware behind the already mentioned https://github.com/Ansem-SoD/Picofly

OG XBox Modchip - Modxo: https://github.com/shalxmva/modxo (see initial impressions from ModzvilleUSA at https://www.youtube.com/watch?v=uUsov3i6jL0)

XBox360 NAND reader / writer - Picoflasher: https://github.com/X360Tools/PicoFlasher (used in the RGH3 hack for some versions of the console as described at https://consolemods.org/wiki/Xbox_360:RGH/RGH3)

Gamecube Modchip - Picoboot: https://github.com/webhdx/PicoBoot

Gamecube Optical Drive Emulator - Flippydrive: https://github.com/OffBroadway/flippydrive as described at https://teamoffbroadway.com/

The flippydrive is such a nice, clean install on a gamecube that it leaves me wondering if the rp2040 could make better ODE's for every other console (psx, saturn in particular)

Interconnecting the flippydrive by squeezing a flex PCB between the optical drive and its motherboard connector was a stroke of genius.

I had look at the code (except flippydrive because it the source for a website) and I don't understand why the PIO would be needed if the RP2040 had more peripheral. None of them use the PIO for something that the STM32F401RBT6 doesn't have a peripheral for.

The RP2040 real advantage its name, its price and its availability during the pandemic chips shortage. It lacks peripherals and it's power consumption is awful.

Analogous complaints were echo'd against the RPI boards, which are also just kinda meh when viewed from an industry / hardcore perspective. Hobbiers gonna hobby, and the ecosystem will eventually build winners / losers for each niche case.

For me, the existence of a MCU/MPU with better features at better price is irrelevant if I can't get known parts on small form factor eval boards using top links on google. Yes, I'm that lazy, but we live in a world with an embarrassment of really good options compared to 20 years ago.

I often just spin a $5 JLC EVM of my own when manufacturers charge too much for theirs. EVM schematics are usually available to clone.

Normally, I can also test a domain-specific subcircuit or two in my "EVM" as well with no added design risk.

The PIO allows you to bit-bang DVI/HDMI; you can put the RP2040 on any bus imaginable (which is the real reason it's popular for console modding) (from a digital perspective of course); you have two PIOs so you can convert between two buses/signals, etc. You can convert digital video, e.g. RGB as used on consoles or DVI, to VGA or DVI if you wanted to. In the past you would've needed an FPGA or CPLD in the middle.

PIO can be PWM, SPI, I2C, USB, DVI, VGA, ISA-bus, PS1 memory card, that weird protocol some old EL-display uses and hundreds of other peripherals. Lots of exotic protocols for which you would have previously needed an FPGA.

That's why you'd choose RP2040.

Or I would just choose an NXP IMRXT-series MCU with FlexIO (which can do 90% of these protocols) and actually be able to protect my product to some degree (encrypted XIP, high-assurance boot, SWD lockout.)

> encrypted XIP, high-assurance boot, SWD lockout

Yeah, would love these on RP2040.

As well as better ADC, "halved" (half mem, IO, PIO and CPU) cheaper version, "doubled" version (2x mem, IO, PIO and M4f CPU cores), integrated flash version, etc. Better power consumption.

That said, I do like PIO and you can use RP2040 as a PIO-peripheral to something more protected.

Related: retro PC stuff.

https://github.com/polpo/picogus

Emulates all kinds of sound cards, including the Gravis Ultrasound.

https://github.com/FreddyVRetro/ISA-PicoMEM

Emulates a memory extension, but also so much more stuff.

Don't cycle sleeps help on the esp32? I typically run on power but I know a lot of people get all day with wifi on reasonable LiPo

No love for NXP in this thread? They make a very similar peripheral called FlexIO [1] on devices like the K32.

>[FlexIO is a] Highly configurable module providing a wide range of functionality including emulation of a variety of communication protocols

It is extremely capable! I have used it to hack together an octo-SPI... which stretches the definition of the S in SPI ;)

[1] https://www.nxp.com/docs/en/supporting-information/FTF-ACC-F...

The NXP IMXRT1011 is $1.70 from CN and much more powerful/featureful than any of the more-expensive K32 chips, by the way.

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