Re: RP400 40-pin connector

On a sunny day (Sun, 11 Aug 2024 13:59:36 -0700) it happened John Larkin
<jjlarkin@highlandtechnology.com> wrote in
<u29ibj5vrgievu9lbvqmthavn4bguj9h8h@4ax.com>:

On Sun, 11 Aug 2024 16:22:04 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
>

"John Larkin" <jjlarkin@highlandtechnology.com> wrote in message news:d21ibjdvt6odqium3ado62ob1e7sa6n9hc@4ax.com...

I want to use an Raspberry Pi 400 (the keyboard thing) as the
dev/debug system for an RP2040 based product.
>
https://www.amazon.com/Raspberry-Computer-Keyboard-Layout-Kabel/dp/B08QCQVWH2
>
It has a 40-pin connector on the back. Various sources say that pins 1

>
This connector?
https://www.pi4j.com/1.3/images/pi4j-rpi-400-pinout.png

>
Yes.
>

>

3 and 5 are either GPIO ports 8 9 and 7 or maybe 2 3 and 4.
>
Sometimes the pins are labeled WPI and BCM. Wot's that?
>
https://www.amazon.com/Coolwell-Waveshare-Raspberry-Adapter-Expansion/dp/B08RZCR7S8

>
If that's just a connector then continuity check it to the above drawing of the connector on the Pi.

>
The real question is whether pin 3 is GPIO8 or GPIO2, and which two
pins are the SW debug.
>
On the Pi4, pin 3 is GPIO2.

GPIO2 and I2C1 sda

It seems like the pins are renamed on the
Pi 400, where pin 3 is GPIO8. Why would they do that?

Yes,
 https://www.pi4j.com/1.4/pins/rpi-400.html
But see the warning, also about reconfiguring the serial port for hardware
Have not tried it, no 400 here.

There were also changes between Pi1 and Pi2 IIRC:
 https://panteltje.nl/panteltje/newsflex/download.html#freq_pi
encountered that...

Why? The world is changing...