Why Should the RP2040 MCU be Specified in Your Next Design? The Heart of the Raspberry Pi Pico

RE: Why Should the RP2040 MCU be Specified in Your Next Design? The Heart of the Raspberry Pi Pico

Jan Cumps — Fri, 13 Jan 2023 17:14:17 GMT

After using these for a few months now, my favourites

Hardware:

The ways the two cores can interact (or be segregated)

Software:

The c sdk
The dual core FreeRTOS port

RE: Why Should the RP2040 MCU be Specified in Your Next Design? The Heart of the Raspberry Pi Pico

DAB — Wed, 11 Jan 2023 20:27:28 GMT

I have yet used the RP2040.

I like the Arduino for quick project testing because it is fast enough and most of my other tools are 5V devices.

I have been following the posts for RP2040 projects and if I need that extra power, I might break down and try one, though I have several RPI 2, 3 and 4 boards around, so having A/D capability is a plus.

RE: Why Should the RP2040 MCU be Specified in Your Next Design? The Heart of the Raspberry Pi Pico

beacon_dave — Wed, 11 Jan 2023 17:49:45 GMT

"...The Pico has an edge on analogue-to-digital conversion (ADC), a faster sampling rate (500 kHz vs. 125 kHz), and a greater resolution (12-bit vs. 10-bit)..."

Has anyone looked closely at the 12-bit resolution vs 10-bit thing yet?

"12bit ADC effective number of bits of 8.7"
https://www.youtube.com/watch?v=CAMTBzPd-WI&t=888s

"beyond 8 or 9 bits it's mostly just noise"
https://www.youtube.com/watch?v=TGjUHChO1kM&t=355s

RE: Why Should the RP2040 MCU be Specified in Your Next Design? The Heart of the Raspberry Pi Pico

dougw — Wed, 11 Jan 2023 17:17:59 GMT

I like the Pi Pico feature set for some applications and its price/performance relative to Arduino modules, but the Pico occupies a similar application space to Arduino modules.

As far as the chip goes, every MCU has applications where it excels and the RP2040 does too. I like that it is not a BGA component. There are definitely applications where more comprehensive documentation, characterization and development tools are required, and when that is available, the range of applications will increase. Good documentation is crucial when launching a new MCU - it is the primary way for designers to determine its suitability. For now the chip will find some commercial applications, for example designs that are transitioning from a Pi Pico prototype to a commercial product, and as Raspberry understands the market better, support is bound to improve. I think the RP2040 is off to a good (but unorthodox) start and it will be fascinating to see how it proliferates into mainstream products.

RE: Why Should the RP2040 MCU be Specified in Your Next Design? The Heart of the Raspberry Pi Pico

BigG — Wed, 11 Jan 2023 17:05:58 GMT

The RP2040 has certainly made it's mark. Despite there being many other ARM M0/M0+ boards on the market, I feel they have set themselves apart by creating a dual core processor with a rather generous 264 kB SRAM and the PIO functionality. I think this chip is here to stay. I have already found that I've been able to create a good few applications that would not have been possible with other M0 MCU's.

The only negative I have, and no it's not the external flash, is the fact that it only comes in a LQFN-56 package. Not exactly hand soldering friendly... although there are plenty on YouTube/Twitter who have demonstrated it is possible. I'm just not brave enough.

Regarding the external flash, I think this must be open to exploiting. Thinking out loud... how about, for example, an ESP8266 or maybe an ESP32 and a RP2040 sharing the same flash by defining different flash start and end points etc. and some sort of synchronised start-up routines etc.

RE: Why Should the RP2040 MCU be Specified in Your Next Design? The Heart of the Raspberry Pi Pico

robogary — Wed, 11 Jan 2023 16:56:30 GMT

RP2040 is awesome. Micropython does pwm so much easier than Arduino. It has multiple i2c and spi which is helpful on some designs. However, I have a nice inventory of older sensors and modules that have mature reliable libraries and examples for Arduino IDE. Micropython requires a novice to research libraries and coding to begin.It

My last project in fact used both arduinos and a raspberry pi pico. The decision on which is best fit for the features needed.

RE: Why Should the RP2040 MCU be Specified in Your Next Design? The Heart of the Raspberry Pi Pico

baldengineer — Wed, 11 Jan 2023 15:08:36 GMT

Like all things in engineering, first you must determine if a product is a good fit for your need.

The RP2040's biggest advantage right now is that it is highly available. No significant customer has allocated large stock to their device... yet.

Another advantage is that the RP2040 isn't carrying a decade+ of technology debt along with it. It's a new design with many interesting features without "leftover" crud from previous product iterations. The PIO is, by far, my favorite.

That said, its power consumption is rather high when sleeping. So it is not really ideal for ultra-low power applications.

Also, I will always recommend CircuitPython over MicroPython. It has a much more robust ecosystem around it with far more maker/hobby/prototype-friendly libraries. Also, it's much easier to work with any editing environment you wish since the MCU appears as a mass storage device in the PC's operating system. Plus, you don't have to bother with the absolutely terrible Thonny garbage. (Though, you can if you hate being productive.)

And now, I"ll really put on my old-man persona. I find it frustrating how many people jump into the Pi Pico with MicroPython and do not realize how much power they have available if they switch to C. Even if they would use the Arduino library to program the RP2040. MicroPython and CircuitPython are great. And if they work for what you want to do, that's great too. But it just amazes me how many people seem to think the Pi Pico is ONLY capable of MicroPython. (and to that extent, how many people seem to think the Pi Pico has anything to do with the Raspberry Pi SBCs.)

RE: Why Should the RP2040 MCU be Specified in Your Next Design? The Heart of the Raspberry Pi Pico

misaz — Wed, 11 Jan 2023 13:50:49 GMT

For me it is mainly cost, in-stock availability at distributors and PIO, but there are several disadvantages when using this MCU like need for external Flash.

RE: Why Should the RP2040 MCU be Specified in Your Next Design? The Heart of the Raspberry Pi Pico

michaelkellett — Wed, 11 Jan 2023 13:24:27 GMT

I think I should correct a matter of detail on current consumption of the RP2040. One of the key differences between it and most other "low power" ARM M0 based microcontrollers is that it has no on chip flash and so must run code from it's ram. Some Giga Devices ARM chips do the same thing. Keeping a large and fast SRAM operable in sleep mode results in high sleep currents, in the case of the RP2040 the claimed sleep current is 390 uA and the "dormant" current is 190uA. These are typical currents, the maxima are 4.5 and 4.2mA.

By way of comparison, the equivalent sleep currents for an STM32G071 are well under 1uA at 25C rising to 48uA at 130C.

It's also worth noting that most other mciro controller suppliers offer much more detailed data sheets with a great deal more characterisation type information.

The RP2040 is an interesting chip but the lack of solid industrial experience of the supplier shows both in the performance and quantity of on chip peripherals and the quality of the documentation. (For an illustration of this compare the data sheets for the specs of the ADCs on the RP2040 and the STM32G071.)