Arduino UNO - Rev4

[ppTRN]

so, as you might have heard of, the new Arduino UNO rev4 is about to get released at the end of May. They will make a wifi version using ESP32-S3 and a cheaper version widout wifi connection, the main uC will be an RA4M1, but yet there is a hidden block to be descovered. Also supply input voltage up to 24V and usb C. What do you think about that? I am surely getting my hand on one of those as soon as it gets out.

https://store-usa.arduino.cc/pages/unor4

[sleemanj]

Personally I think it's stupid to call it an UNO R4 when it doesn't have a ATMega328. 

It's just going to confuse new people when things written for an UNO don't work on their UNO.

Should have given it a new name.

[floobydust]

Renesas RA4M1? What a huge mistake. The politics of Arduino, killing it off.
Should've stayed with SAMD21 or SAMD51, nobody likes Renesas for their asshole supply chain and obscure nature. 93 week lead times.

A new UNO should just be upgraded 328PB, 328P is near end of life.

[SiliconWizard]

Whether they kill themselves or not, I personally don't particularly care.
The Arduino ecosystem has gotten so big that there are literally hundreds of supported boards and MCUs. You don't need to use Arduino official hardware to use Arduino.
If they want to kill themselves, so be it. "Arduino" as a framework is likely to keep going due to the gigantic user base.

[ataradov]

I don't get that "hype" rollout. You either have a board to release or not. What's up with that yellow sticker covering half the board? I'm assuming it is some "but wait, there is more" thing to be disclosed later, but why? Probably CAN stuff, since they mention support, I assume they would have a transceiver, but I don't see too many people interested in that .

I assume they picked Renesas part for 5 V compatibility. They explicitly advertise that. For mainstream board they care about supporting majority of shields, I guess.

Also," UNO R4" name seems to conflict with some random knock-off board.

Plus Renesas may be a good option for them for the supply reasons - they secured all the supply, no parts left for copies

[SiliconWizard]

As to 5V compatibility, I understand the rationale for supporting a ton of existing "shields", but I don't think they are doing users a service here, outside of this. Which is a bit of a circular rationale. (They created a need and now they are stuck to it.)

Except for niche applications and vintage stuff, not going to 3.3V logic for hobbyists these days does not make sense IMO. This is harming them more than it helps them, as can be seen in thousands of threads all over the world with people looking for 5V parts that are increasingly hard to find, or having to use level shifters all over the place.

I remember in the late 90's, was still a student, going to 3.3V logic still felt like a "big" step back then for some reason. It's interesting to note that, largely "thanks" to Arduino, many hobbyists and even students in 2023 still feel the same.

[ppTRN]

Although i am fond of all the Arduino ecosystem (even Just beause i am relatively young and was growing up using an uno r3 for most of my Life) i must Say i am surprised about this new entry on the Arduino family. I could have bet that even them would have jumped in the single PC board, still integrated using a uC. Buy wait.. they actually already tried It with the yun...

Anyhow, really disappointed by the 5V choice. I think It Is time to move forward

[rteodor]

Plus Renesas may be a good option for them for the supply reasons - they secured all the supply, no parts left for copies

I wonder how Renesas did that ? Out of the about 16 chip fabs inherited from NEC and Hitachi they kept only 2. And I think they almost burned one during the pandemic.

Personally I think it's stupid to call it an UNO R4 when it doesn't have a ATMega328.

+1.
It might have something to do with registering an expensive new trademark ?

Anyhow, really disappointed by the 5V choice. I think It Is time to move forward

A 5V tolerant chip is a must for Arduino crowd. And being a Renesas device they could certainly have had a 12V tolerant chip.

[RoGeorge]

Wasn't UNO at first models with FTDI + ATmega8?  It became ATmega328 later.
The good part with the 3V3 is that would be possible to run it from a single Li-Ion.

[PCB.Wiz]

Except for niche applications and vintage stuff, not going to 3.3V logic for hobbyists these days does not make sense IMO.

Depends on your values of niche 
I'd say being able to drive Blue / White LEDS, serial LEDS and Higher power logic Level MOSFETS, are all quite important things for designers. Not niche at all.
If someone is fine with 3v3 solution, they can use a Pi PICO or other not backward compatible solution.

[brucehoult]

Wasn't UNO at first models with FTDI + ATmega8?

No. Even the Diecimila and Duemilanove were already ATMega168 or 328. The ATMega8 ones were simply "Arduino" or "Arduino Extreme" or "Arduino NG".

[PCB.Wiz]

Renesas RA4M1? What a huge mistake. The politics of Arduino, killing it off.

Time will tell.
Looks a nice part to me ?

14bit ADC is certainly nice to have, as is a 12b DAC, tho I would have liked more than 1 DAC channel.
5V is great to have, for Blue/White LEDs  and serial leds and Power MOSFETS, and CAN, USB and Touch are also appealing.

Looks like MICROE also like this part and have a small board with full debug
https://www.mikroe.com/ra4m1-clicker
and Mouser have a larger board, also with Debug
https://www.mouser.com/ProductDetail/Renesas-Electronics/RTK7EKA4M1S00001BU


The Nuvoton M471 series could have been another choice, but maybe is too new ? - ADC/DAC not as good, but more flash/ram ? Oh wait, seems DAC and USB are exclusive ?
https://direct.nuvoton.com/en/numaker-m471r1
 

Should've stayed with SAMD21 or SAMD51, nobody likes Renesas for their asshole supply chain and obscure nature. 93 week lead times.

SAMD21 and SAMD51 are not 5V...

A new UNO should just be upgraded 328PB, 328P is near end of life.

That's hardly an upgrade.
Perhaps one of the DA/DB/DD etc could have made sense for an incremental step, but the RA4M1 makes sense as a larger step.

I don't get that "hype" rollout. You either have a board to release or not. What's up with that yellow sticker covering half the board? I'm assuming it is some "but wait, there is more" thing to be disclosed later, but why?

Yes, that's a bit annoying. Besides CAN, the part has USB and touch and LCD.. maybe some of those get access ?

I've seen AliExpress have more modules offering now with a small LCD included, that would be a cute addition
eg
https://www.aliexpress.com/item/1005001543731001.html  has a TSSOP20 MCU from Nuvoton, making it flexible.
and
https://www.aliexpress.com/item/1005005365025142.html

Also," UNO R4" name seems to conflict with some random knock-off board.

Yes, not a smart choice when google offers up so many UNO R4's 

[westfw]

I think it's stupid to call it an UNO R4

I've got to agree with that completely.  The "Nano Every" was a naming disaster, and it kept the same AVR family. :-(
An AVR128db48 would have been nice.


Renesas, eh?  Well, I guess it's about time that Arduino got out of bed with Atmel (now Microchip; I wonder if that had something to do with it?) But this seems like a strange choice; not particularly well known, nor powerful, nor cheap.  I guess it has that 5V operation and IO...

RA4M1 (Arm Cortex®-M4) running at 48MHz, boasts a 3x performance increase over the UNO R3

Man, I sure hope that they can get 3x performance by going from a 16MHz 8bit CPU to a 48MHz 32bit CPU.  I wonder if that's actually a commitment to "somewhat optimize" things like "digitalWrite()"?  (alas, I suspect not.)

[xrunner]

Heck, I might buy one for a cheap thrill just to see if it works without code modification with one of my completed projects that's using an Uno. My little RF power meter could use the speed.

I say cheap thrill - but what will the overpriced cost be for one? 

[brucehoult]

Heck, I might buy one for a cheap thrill just to see if it works without code modification with one of my completed projects that's using an Uno. My little RF power meter could use the speed.

I say cheap thrill - but what will the overpriced cost be for one? 

You are aware the Arduino Due with an 84 MHz Cortex M3 and 54 GPIOs (so like a Mega), 96 KB SRAM, 512 KB flash, 3.3V IO has been out for ... 12 years.

This Uno R4 has half the clock speed, half the flash, one third of the SRAM, a third of the GPIOs of a dozen year old board.

But it has an FPU.

[ataradov]

You are aware the Arduino Due with an 84 MHz Cortex M3 and 54 GPIOs (so like a Mega), 96 KB SRAM, 512 KB flash, 3.3V IO has been out for ... 12 years.

I think the point of this board (and the unfortunate naming that comes with it) is to become the new mainstream version. The one that is default. And in that sense, having an obscure MCU is better. This way it just becomes the new "Arduino" MCU without associations to other boards or tools.

They had a lot of derivatives, even official ones, but none managed to be successful.

And I'm sure at this point they are severely running out of resources on that poor atmega.

Plus Due is 3.3 V only, and 5V is apparently important enough to maintain for the main board.

[xrunner]

You are aware the Arduino Due with an 84 MHz Cortex M3 and 54 GPIOs (so like a Mega), 96 KB SRAM, 512 KB flash, 3.3V IO has been out for ... 12 years.

This Uno R4 has half the clock speed, half the flash, one third of the SRAM, a third of the GPIOs of a dozen year old board.

But it has an FPU.

Thanks for the info Bruce. No I wasn't really aware. I have a stash of Uno boards so was trying to use them all in projects. But yea if I desperately needed more speed I would have needed to research available options better. However, it would still be interesting to try this board and see how it performs. But again your input is duly noted. 

[PCB.Wiz]

I see there is also
https://www.hackster.io/news/bluetrum-launches-rt-thread-based-arduino-uno-like-risc-v-development-board-the-ab32vg1-8d532d3612d7
says around $12.30 for 120MHz, but they may have made a strategic decision to avoid Chinese parts.
Hmm... looks like VBUS is 5V but VDDIO is only 3v3

[rteodor]

Looks like MICROE also like this part and have a small board with full debug

I can not understand why hardware onboard debuggers are not welcome in Arduinos.

Arduino Zero - later renamed to Arduino M0 Pro (SAMD21G18 256KB flash / 32KB RAM) had EDBG chip that was an ATmega16 for onboard debugger. And it was in the same format as UNO. It disappeared around the time Microchip bought Atmel.
It was the best Arduino for small tinkering IMO.

[RoGeorge]

Does the UNO R4 board has a hardware debugger or not?

The new Arduino 2.x IDE is hardware debugging ready.  The main downside for me at 2.x is that the offline "Find in Reference" contextual menu has been removed (double click a word in the source code, and right click "Find in Reference" to open the documentation webpage for it is no longer there).

IDE 1.x was able to open the reference docs in an offline webpage. 

[Kerlin]

I also find a consistent problem with Arduino has been the lack of a debugger/programmer.
The Arduino forums have lots of inquiries about people who have bricked their board, usually because they lost the bootloader.
So without a method to reload it the board it is useless
Long time ago had this happen with Uno, but of course that these days is easily fixed, it wasn't always that way and the forums were full of people having that problem.

I recently had this happen with a SAMD21 Mini and there's no way out of it, unless you have the Atmel ICE.
It worked once only, when I changed the LED blink to a different time. Yes I double clicked it.
I see on their forum many users have had this "worked once problem" with SAMD21 boards.

So now do not use anymore Arduino boards in projects unless I have a way to recover the board.
I see there are users with bricked Portenta H7 boards on the Arduino forum with no answer.
I have checked some of the usual suppliers and the Renesas ICE For the RA4M1 is not available and if it is its $700+.

Mr PJRC is a smart guy, has mostly taken care of this and the Teensy forum is not full of people who bricked their board, he uses a separate boot chip.

Lets see how many users with bricked Uno Rev4 come up on the Arduino forums.

[ataradov]

You can use any generic debugger, it is just a standard ARM device. You can make one from PiPico for $4. And it is impossible to brick PiPico.

The issue of recovering the device is pretty well solved nowadays. Times of expensive debuggers is long gone, if you are paying more than $15 for a debugger, you are being ripped off, unless you have some special requirements for tracing and all that stuff.

[Kerlin]

Thanks will look at that PiPico solution.

[ataradov]

Thanks will look at that.

The official firmware from RPi - https://github.com/raspberrypi/picoprobe, my version - https://github.com/ataradov/free-dap

Both do the same thing, both follow the same protocol as Atmel-ICE (with exception for some Atmel specific things, which are needed for AVRs).

Also, RPi recently released a new debugger hardware - https://www.raspberrypi.com/products/debug-probe/ . It runs picoprobe firmware. And it has a chance to be a common "default" debugger probe for the community. It is cheap enough and if you don't want to pay even $12, you can make one for $4.

[ppTRN]

Beside, the presence of the ESP32-S3, beside his connectivity, will cast a shadow on the RA4M1, way superior in term of specs. So why both? One could have got away with just the ESP32-S3