Arduino UNO - Rev4

[RoGeorge]

The Arduino forums have lots of inquiries about people who have bricked their board, usually because they lost the bootloader.

AFAIK for UNO it is possible to use another working Arduino as a ISP programmer to program/recover a bricked one.  I assume this should be possible for SAMD21, too.

My UNO clones have a ISP connector with populated 2x3 pins for ISP.  They were $11 each in 2015, with an USB cable and a 320x240 2.4'' touch screen TFT w uSD shield included, and free shipping.

[PCB.Wiz]

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

Hard to say, the rendered image seems to show a DFN20 ? package, for USB serial link, which is an unusual package.
The other vendors Renesas Boards for the same MCU show a 'proper' Segger debug link silicon (in larger packages).

Does anyone have ideas on what that DFN20? package by USB might be ? Or is the render 'inaccurate' ?

[RoGeorge]

Offtopic:  "does it have?", not "does it has?", sorry. 

[MLXXXp]

But it has an FPU.

Does it? For the Cortex M4, the FPU is optional. I can find no mention that the Renesas RA4M1 has an FPU. It's designated as having a Cortex M4, not an M4F
https://developer.arm.com/documentation/ddi0439/b/Floating-Point-Unit

[PCB.Wiz]

Does it? For the Cortex M4, the FPU is optional. I can find no mention that the Renesas RA4M1 has an FPU.

?
The data says
■ Arm Cortex-M4 Core with Floating Point Unit (FPU)
 Armv7E-M architecture with DSP instruction set

[SiliconWizard]

Yes that is on the feature page of the datasheet (page 2):

Arm Cortex-M4 Core with Floating Point Unit (FPU)

Note that while indeed Cortex-M4 doesn't necessarily come with a FPU, and the common naming with a FPU would be M4F, I've personally never run into any MCU which was M4-based and without a FPU.
If someone has a reference for such an odd beast, I'll be curious to see it.
(I'm sure that will be an invitation for some to look for one and try to prove that is it actually very common. )

[brucehoult]

But it has an FPU.

Does it? For the Cortex M4, the FPU is optional. I can find no mention that the Renesas RA4M1 has an FPU. It's designated as having a Cortex M4, not an M4F
https://developer.arm.com/documentation/ddi0439/b/Floating-Point-Unit

I did check the Renesas datasheet before saying that.

https://www.renesas.com/us/en/document/dst/renesas-ra4m1-group-datasheet?r=1054146

[ataradov]

(I'm sure that will be an invitation for some to look for one and try to prove that is it actually very common. )

It is pretty easy and not even an obscure old device - STM32WL have no FPU. I guess they decided that wireless stuff does not need floating point and decided to shave off a few cents.

I've been monitoring availability of R7FA4M1AB3CFL on Mouser. And initially they had 5 in stock and 300+ on order. Now they have 18 in stock. Did they just find 13 random devices laying around?

[PCB.Wiz]

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

Looks good.

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.

Hmm, strangely, they only connect 2-Debug  pins and ignore SPI/JTAG options, which is a big shortfall for it to ever become "a common "default" debugger probe for the community."

I like the look of the CH347, which has HS-USB and TSSOP20 package, and has 2 serial pathways, tho it is still somewhat niche.
https://www.tindie.com/products/johnnywu/ch347-development-board/

[ataradov]

Hmm, strangely, they only connect 2-Debug  pins and ignore SPI/JTAG options, which is a big shortfall for it to ever become "a common "default" debugger probe for the community."

Well, it is mostly for ARM devices, so reducing pin count and only supporting SWD is a fair trade. If Arduino manages to move a lot of people to that board, then It would be more relevant, of course.

But other than that, there are a ton of options. So many that it is hard to enumerate them all.

The problem with all those WCH devices are weird proprietary drivers. And full PiPico is still cheaper and will support full JTAG.

[Kerlin]

Thanks will look at that.

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

Good work. Live long and prosper my friend.

RoGeorge no you cant do that with a SAMD21 Mini. And  I did say, for the Uno - "I know its easier now"- 

       V  V  V

[ataradov]

The boards have been released. The stickers were hiding a field of LEDs. Meh.

But I ordered the minimal one, we'll see how that Renesas MCU looks like.

On the Wi-Fi one there is not even SWD connector. The programming pins are connected to the ESP32.

And USB pins go simultaneously to both. There are actually muxes too, but none of the parts are marked DNP, so who knows what is on the actual boards.

[RoGeorge]

This year's Arduino IDE 2 has hardware debugging support (though they removed the internal offline docs and help, which used to be very convenient to have in Arduino IDE 1).  Not any Arduino devboard can use the hardware debugger from the IDE v2.

Does the Arduino v4 have a debugger?

[ataradov]

Nope. No debugger on a minimal one. ESP32 may act as a debugger, but I don't know if they implemented any support for it.

Also, no CAN transceivers on the board.

[firewalker]

One advantage of UNO was that the use of a simple mcu allowed users to start programing it using plain C fairly easy. Now with a 32 bit mcu...

Alexander.

[ataradov]

If you are using Arduino APIs, it is just as easy.

[firewalker]

With Mega328 and gcc someone could in 5 minutes start poking to registers and learn something else. I bet that the datasheet for this mcu is at least 10x bigger and you will need a couple of hours just to set up the environment.

The UNO name scheme always suggested something fairly simple.

Alexander.

[asmi]

The most important question is - did they fix the header offset? Or turned the bug into a feature?

[brucehoult]

The most important question is - did they fix the header offset? Or turned the bug into a feature?

And have all the hundreds of existing shields not fit?

[westfw]

I am pleased at the "reasonable" prices.
Sure, not as cheap as a "clone" or a Pico, but consistent with Arduino's historical "low end" pricing.

[ArdWar]

The most important question is - did they fix the header offset? Or turned the bug into a feature?

That indeed ends up as a feature. With a proper on-grid headers, people can fit shields backward if they try to. With the offset they have to try ever so slightly harder.

[mikerj]

The boards have been released. The stickers were hiding a field of LEDs. Meh.

Meh indeed, it's utility seems limited after you are done making pretty patterns but I suppose it was a cheap option.  A small LCD or OLED type display would have been much more useful but more $$.

[PCB.Wiz]

The boards have been released. The stickers were hiding a field of LEDs. Meh.

Meh indeed, it's utility seems limited after you are done making pretty patterns but I suppose it was a cheap option.  A small LCD or OLED type display would have been much more useful but more $$.

It seems to be seeded by the micro:bit which is big in education and has a 5x5 LED matrix.
Given Renesas now has a considerable investment here, I'd expect they want to chase the education exposure market.

I wonder how that Uno 12 x 8 LED array would work as a decimal readout, with a translucent overlay ? 
Could support 8 'digits' and an additional 16 status / decimal point / range indicators ?

[brucehoult]

The boards have been released. The stickers were hiding a field of LEDs. Meh.

Meh indeed, it's utility seems limited after you are done making pretty patterns but I suppose it was a cheap option.  A small LCD or OLED type display would have been much more useful but more $$.

It seems to be seeded by the micro:bit which is big in education and has a 5x5 LED matrix.
Given Renesas now has a considerable investment here, I'd expect they want to chase the education exposure market.

I wonder how that Uno 12 x 8 LED array would work as a decimal readout, with a translucent overlay ? 
Could support 8 'digits' and an additional 16 status / decimal point / range indicators ?

If you want to replace micro:bit then there is this:

https://www.sparkfun.com/products/17597

The Uno R4 is cheaper, but the Dr Who board comes with other hardware, a book, and has a micro:bit compatible connector.

Bare board:

https://www.sparkfun.com/products/17596

[Picuino]

I join this thread

Edit:
https://store.arduino.cc/products/uno-r4-minima
https://store.arduino.cc/products/uno-r4-wifi