3 ms·

This is 2x the size of a xiao/qtpy, has less stuff(?), and is more expensive. What are the advantages? https://www.seeedstudio.com/XIAO-RP2040-v1-0-p-5026.htm

This is 2x the size of a xiao/qtpy, has less stuff(?), and is more expensive. What are the advantages? https://www.seeedstudio.com/XIAO-RP2040-v1-0-p-5026.html https://www.seeedstudio.com/XIAO-RP2040-v1-0-p-5026.html https://www.adafruit.com/product/4900 https://www.adafruit.com/product/4900

codebje 5y ago
Exposed pins, for one. There's 30 GPIOs on an RP2040, only having 12 or so of them available is a weakness of rhe tiny boards.
- ghostly_s 5y ago
  Raspberry Pi Pico has 26 GPIO and is $4 assembled.
  - elcritch 5y ago
    Those extra 4 pinouts can be key to being able to use a board for a given project.
    - throwaway81523 5y ago
      Gotta wonder how often that happens: 30 pins are enough, but 26 aren't? I've had stuff that wanted 3-5 pins, or maybe 10 pins. I've had stuff that wanted 100's of pins. I can't think of anything that wanted, specifically, between 27 and 30 inclusive. Does the Pico really fail to bring out 4 of them anyway? That is kind of surprising. I know that it uses one of the ADC's for battery monitoring, leaving just 3, but maybe you can get it back by cutting a trace or something. Is it practical and useful to connect 20+ of the pins to PIO ports? The PIO's are very limited.
  - codebje 5y ago
    Yeah, but the question was why buy the stamp when smaller boards exist. You won't get much smaller than the stamp with so many exposed pins, since it's basically just 2mm pitch pads packed on every edge. I'd probably say suck it up and solder the QFN directly if you need all the GPIO in minimal space, though.
- thrtythreeforty 5y ago
  Especially with the RP2040, having less pins exposed is kinda dumb. The programmable GPIO ("PIO") is the chip's whole raison d'etre.
colejohnson66 5y ago
That’s like asking why someone would choose a bigger FPGA when a smaller one does the same thing for less cost. The answer is: the bigger one has a different feature set. In this case, it’s access to all 30 of the GPIO.
- throwaway81523 5y ago
  Ah I see. I hadn't thought about using all the pins. This brings out 23 of them and is about the same size as the stamp: https://www.adafruit.com/product/4888 https://www.adafruit.com/product/4888 This brings out 20 and has castellated pads: https://www.adafruit.com/product/5302 https://www.adafruit.com/product/5302 This is bigger but fancier, has a lipo charger and other stuff. I think it brings out all available pins, though the # mentioned is 21. More of an SBC than a solder-down, I guess. I have one (old version) but am trying to figure out where I left it: https://www.adafruit.com/product/5302 https://www.adafruit.com/product/5302
antattack 5y ago
It's best to treat Tindie as a venue to support the developer/creator, not as a source of inexpensive stuff. If you want it cheap - this project is fully open source - one can make the board themselves, might be possible even order it assembled in larger quantities from PCBWay or JLCPCB.
thomaslord 5y ago
30 GPIO pins broken out vs. 13 is a good start. I also see no mention of the battery charging stuff on either of the boards you linked.

codebje 5y ago

Exposed pins, for one. There's 30 GPIOs on an RP2040, only having 12 or so of them available is a weakness of rhe tiny boards.

ghostly_s 5y ago
Raspberry Pi Pico has 26 GPIO and is $4 assembled.
- elcritch 5y ago
  Those extra 4 pinouts can be key to being able to use a board for a given project.
  - throwaway81523 5y ago
    Gotta wonder how often that happens: 30 pins are enough, but 26 aren't? I've had stuff that wanted 3-5 pins, or maybe 10 pins. I've had stuff that wanted 100's of pins. I can't think of anything that wanted, specifically, between 27 and 30 inclusive. Does the Pico really fail to bring out 4 of them anyway? That is kind of surprising. I know that it uses one of the ADC's for battery monitoring, leaving just 3, but maybe you can get it back by cutting a trace or something. Is it practical and useful to connect 20+ of the pins to PIO ports? The PIO's are very limited.
- codebje 5y ago
  Yeah, but the question was why buy the stamp when smaller boards exist. You won't get much smaller than the stamp with so many exposed pins, since it's basically just 2mm pitch pads packed on every edge. I'd probably say suck it up and solder the QFN directly if you need all the GPIO in minimal space, though.
thrtythreeforty 5y ago
Especially with the RP2040, having less pins exposed is kinda dumb. The programmable GPIO ("PIO") is the chip's whole raison d'etre.

colejohnson66 5y ago

That’s like asking why someone would choose a bigger FPGA when a smaller one does the same thing for less cost. The answer is: the bigger one has a different feature set. In this case, it’s access to all 30 of the GPIO.

throwaway81523 5y ago
Ah I see. I hadn't thought about using all the pins. This brings out 23 of them and is about the same size as the stamp: https://www.adafruit.com/product/4888 https://www.adafruit.com/product/4888 This brings out 20 and has castellated pads: https://www.adafruit.com/product/5302 https://www.adafruit.com/product/5302 This is bigger but fancier, has a lipo charger and other stuff. I think it brings out all available pins, though the # mentioned is 21. More of an SBC than a solder-down, I guess. I have one (old version) but am trying to figure out where I left it: https://www.adafruit.com/product/5302 https://www.adafruit.com/product/5302

antattack 5y ago

It's best to treat Tindie as a venue to support the developer/creator, not as a source of inexpensive stuff. If you want it cheap - this project is fully open source - one can make the board themselves, might be possible even order it assembled in larger quantities from PCBWay or JLCPCB.

thomaslord 5y ago

30 GPIO pins broken out vs. 13 is a good start. I also see no mention of the battery charging stuff on either of the boards you linked.