analogRead() on RP2350*A*

[elral]

Hello all,

I have an own designed board using the RP2350A, the FW gets compiled using PlatformIO. The board definition is generic_rp2350.

Part of the the FW is reading analog values where the pin number is not hardcoded.
I realized that analogRead(A0) is working, but analogRead(26) not. Hovering above A0 showed me the value 40. So I have to use analogRead(40) to read from the first analog pin 26.

Using the board definition rpipico2 it's working like intended.

Is this the intended behaviour? If so, a hint in the documentation woudl be great.

[earlephilhower]

Just verified that the IDE works fine with a Pico2 using the generic_rp2350/RP3250A selection.

So, looks like your P.IO config is not specifying the chip properly in some way. Check that it matches the defines used in the IDE for the generic-2350/variant A model. Even better would be to make a custom board definition/JSON.

The logic boils down to a simple define in Arduino.h based on the RP2350A define

arduino-pico/cores/rp2040/Arduino.h

Lines 164 to 171 in c720c79

	// General GPIO/ADC layout info
	#if defined(PICO_RP2350) && !PICO_RP2350A
	#define __GPIOCNT 48
	#define __FIRSTANALOGGPIO 40
	#else
	#define __GPIOCNT 30
	#define __FIRSTANALOGGPIO 26
	#endif

Somehow you've #define PICO_RP2350d and #define RP2350A 0 in the compilation, or it would fall thru to the original definition. You should check the JSON in use, too. Maybe it's setting it if your code isn't.

[elral]

Thanks for your fast reply.
Must be indeed something with my platformio.ini or my code.

A simple example

void setup() {
  Serial.begin(115200);
}
void loop() {
  Serial.println(analogRead(/*A1*/ 41));
  delay(200);
}

with

platform = raspberrypi
board = generic_rp2350
framework = arduino

does work. I even have not to add build_flags = -DRP2350A, but I could do it without any warning.

My used platformio.ini uses also the same board definition, but still the wrong pins are used.
If a set build_flags = -DRP2350A a get the warning multiple times:

In file included from C:\Users\ralfk\.platformio\packages\framework-arduinopico/include/rp2350/pico_base/pico/config_autogen.h:7,
                 from C:\Users\ralfk\.platformio\packages\framework-arduinopico/pico-sdk/src/common/pico_base_headers/include/pico/config.h:19,
                 from C:\Users\ralfk\.platformio\packages\framework-arduinopico/pico-sdk/src/common/pico_base_headers/include/pico.h:62,
                 from C:\Users\ralfk\.platformio\packages\framework-arduinopico\cores\rp2040/Arduino.h:30,
                 from C:\Users\ralfk\.platformio\packages\framework-arduinopico\cores\rp2040\wiring_shift.cpp:22:
C:/Users/ralfk/.platformio/packages/framework-arduinopico/pico-sdk/src/boards/include/boards/solderparty_rp2350_stamp_xl.h:23:9: warning: "PICO_RP2350A" redefined
   23 | #define PICO_RP2350A 0
      |         ^~~~~~~~~~~~
<command-line>: note: this is the location of the previous definition

Now I have to figure out why solderparty_rp2350_stamp_xl.h gets used and why setting this define does not give a warning for the example above.

[earlephilhower]

Just a note, you need to #define RP2350 and either #define RP2350A 0 or #define RP2350A 1. That's the (ugly IMHO) SDK standard. So -DRP2350A will break things.

[earlephilhower]

Err, make that PICO_RP2350 and PICO_RP2350A

Also you can't define -DPICO_RP2350A=0 on the command line. The SDK includes its own board header which will try and redefine things as seen in your error message. That needs to be in our own headers (ARduino.h or pins_arduino.h). When we build, we build with the solderparty2350 just because it is a B so the SDK will not remove B code. We then redefine things in our headers to bring it back to an A variant by default.

All in all, I would recommend spending 5 mins writing your own board variant and use that without messing w/P.IO's custom define settings.

[elral]

Thanks again.

The reason not to set up my own board variant is that we build our firmwares on github when a new release is down via Actions. PlatformIO gets installed and pio run is executed. Afterwards all FW files and some other files gets bundled and as a zip attached to the release.
Setting up our own board file means that we have to copy it from "somewhere" (most likely from the same repo) to the platformio file structure before running pio run. But if there is no other way we will give it a try.

A little bit unclear for me is still for which processor the generic_rp2350 variant is, for the A or for B. Also why PICO_RP2350A is set in this way. I didn't found where __PICO_RP2350A comes from.

[earlephilhower]

Code's all here to inspect. 😄

The PICO_RP2350 and PICO_RP2350 defines follow the (IMHO brain damaged) Pico SDK options. However, you cannot ever set the PICO_RP2350A in the build line.

The SDK has a limited set of boards, so we build/set the SDK config to one that maxes out things. We then include the pico/board.h (which sets the RP2350 and RP2350A defines as it sees fit) and then immeduately undo it so the pins_arduino can define it:

arduino-pico/cores/rp2040/Arduino.h

Lines 30 to 32 in 7a02f8a

	#include <pico.h>
	#undef PICO_RP2350A // Set in the RP2350 SDK boards file, overridden in the variant pins_arduino.h
	#include <pins_arduino.h>

For generic2350, there's a special define we use to let the menus select what pins_arduino.h defines

arduino-pico/tools/makeboards.py

Lines 87 to 90 in 7a02f8a

	def BuildRP2350Variant(name):
	for l in [ ("RP2350A", "-D__PICO_RP2350A=1"), ("RP2530B", "-D__PICO_RP2350A=0") ]:
	print("%s.menu.variantchip.%s=%s" % (name, l[0], l[0]))
	print("%s.menu.variantchip.%s.build.variantdefines=%s" % (name, l[0], l[1]))