QUESTION: Number of Digital pins

[Turgut Guneysu]

Hi John,

micro:bit docs state:

MicroBlocks blocks “analog” reports 6, and “digital” reports 29.

Is the digital count correct ?

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[John Maloney]

Some of those pins are internal pins and the pin numbers comes from the Arduino framework for the micro:bit. Here’s the comment from the code:

// See variant.cpp in variants/BBCMicrobit folder for a detailed pin map.
// Pins 0-20 are for micro:bit pads and edge connector
//  (but pin numbers 17-18 correspond to 3.3 volt pads, not actual I/O pins)
// Pins 21-22: RX, TX (for USB Serial?)
// Pins 23-28: COL4, COL5, COL6, ROW1, ROW2, ROW3
// Button A: pin 5
// Button B: pin 11
// Analog pins: The micro:bit does not have dedicated analog input pins;
// the analog pins are aliases for digital pins 0-4 and 10.

But I agree, it is confusing. The idea is to make the internal pins available for advanced users. For example, if you wanted to write your own low-level code to control the 5x5 display, you’d need to use the internal row and column pins, pins 23-28.

[John Maloney]

Question answered.