Pi Pico Eurocard - SD Card signals

Initial part of a format sequence

One of the dev board advantages, is that you can measure current of the Pico fairly easy. By using external power (can be the PicoProbe or one of the options at the left side of the board). And using a current meter instead of a jumper.

This is the envelope when activating the SD card and do some reads/writes.
For real low power designs* you may want to remove the LED, and pull-ups of peripherals you don't use.

* pico MCU in its current version isn't targeting very low power. An upside of that is that it's a bit easier to start learning to collect power consumption data with it.

Hi Jan,

That's very interesting, seeing this measurement when the micro SD card is used. Good point to disconnect the LEDs. I didn't think of the power LED : (

Incidentally, in the later 2.2 revision, there are additional 0-ohm resistors in the 5V and 3.3V rails, just in case anyone ever wants to replace with a small resistor to use as a shunt resistor (or swap out to a small polyfuse if desired). But desoldering a 0-ohm resistor is not as convenient as the method of just unplugging the jumper as you did.

Just thinking, if the ADC in the RP2040 is any good (I've not used it), then there's an argument for making the Picoprobe do a bit more, and take current readings too : ) 

It's not that good. In the current silicon design, the ADC is the known sick baby. There's an errata for it, but not a solution.

Good enough for some current sampling though.

I think it's fair to accept that a prototyper can solder / desolder SMD resistors (if you don't use 0402).

In my wildest dreams, the prototype area would be SMD, not through-hole.
Although I believe the two can live together - if the current through-hole configuration stays the same: pads at the bottom layer, with drill holes. And an SMD copper-only pattern is available on the top side.

I think if hobbyists have tried and not found 0805 (and 0603) easy, they are perhaps doing one or more of these:

• Using a very large soldering iron and/or not using decent solder <= 0.5 mm dia
• Not using eye improvement equipment like a head-magnifier (way easier and cheaper than cameras etc)
• Using incorrect tweezers that make the part go flying.

Speaking of the latter, I misplaced my decent (VOMM) tweezers a couple of months ago, and parts now fly in the air with some regularity. I have ordered a replacement, I hope it's as good as the VOMM I had which was excellent ( ~ 0% chance of components being launched with them) but that particular one is no longer easy to obtain. I went with these ones below, which appear to be identical shape and size to what I lost. I think they are both the same shape, one is slightly lower-cost than the other, so it will be a backup if the other ever gets misplaced: