missing framebuf module on nucleo board

[sanbeg]

I'm trying to port a library for an ILI9341 display, but the library uses the framebuf module, and I don't see any way to install that. This is what I currently see installed on the board.

MicroPython v1.26.1 on 2025-09-11; NUCLEO_G474RE with STM32G474
Type "help()" for more information. 
>>> help('modules')
__main__          builtins          math              struct
_onewire          cmath             micropython       sys
array             collections       onewire           time
asyncio/__init__  dht               os                uasyncio
asyncio/core      errno             platform          uctypes
asyncio/event     gc                pyb               vfs
asyncio/funcs     heapq             random
asyncio/lock      io                select
asyncio/stream    machine           stm
Plus any modules on the filesystem

[Josverl]

Have you tried mpremote mip install framebuf ?

https://docs.micropython.org/en/latest/reference/packages.html

[sanbeg]

Yes, I tried that; but it doesn't seem to be available there, either.

[Josverl]

Sorry, my bad
Framebuffer is implemented in C. extmod/modframebuf.c

[ricksorensen]

The default NUCLEO_G474RE board has framebuf omitted in mpconfigboard.h:

 #define MICROPY_PY_FRAMEBUF         (0)

most likely to preserve memory space. To get the framebuf module you should set this define to 1.

[sanbeg]

This is my first time looking at these files, so it's possible I'm misinterpreting something or using wrong terminology. My understanding is that each line of the form
#define MICROPY_PY_xxxx (0)
refers to some module xxxx which is disabled on that board. So since the G474RE has 9 of those lines, that means there are 9 disabled features on that board.
Other boards which have the same or less less memory, such as the F401 & F411 don't have any of those lines; I take that to mean that without the line to explicitly disable some module, that by default every module enabled.

[davefes]

First you say G474 has framebuf and asyncio removed, then you say the F411 is the same as the G474, also have everything enabled.

Do you mean they have the same flash and RAM sizes? The WeACT BlackPill F411 has both framebuf and asyncio enabled.

OK, I think the relevant question is ... are things enabled by default unless explicitly disabled. As I see no #define MICROPY_PY_xxxx (0) in the F411 I would say you are probably correct.

[sanbeg]

Yes, that's what it appears to me. The manual for the g474 (https://www.st.com/resource/en/user_manual/um2505-stm32g4-nucleo64-boards-mb1367-stmicroelectronics.pdf) which covers a few boards lists them as so:

• 128 Kbytes of flash memory and 32 Kbytes of SRAM for STM32G431RBT6
• 512 Kbytes of flash memory and 96 Kbytes of SRAM for STM32G491RET6
• 512 Kbytes of flash memory and 128 Kbytes of SRAM for STM32G474RET6

While according to the equivalent F series manual (https://www.st.com/resource/en/user_manual/um1724-stm32-nucleo64-boards-mb1136-stmicroelectronics.pdf) the trailing E in the F411RE means it also has 512K flash.

So it looks like other than the G474RE being a little newer, faster, and more efficient the specs, at least as far as memory size, should be the same as the f411. So I can't find anything to indicate why we'd want to remove so many modules from a higher spec board, but keep them in similar or lower, older boards. I wonder if someone misread the manual, and created a board file which would be appropriate for the G431RB, which doesn't seem to supported in micropython, but applied it to the G474RE instead

[davefes]

Looked through some of the other board defs I have for the F411 and saw this:

// Disabled network realted functions to save space
// Note STM32F411-series does not have ETH-interface
// #define MICROPY_PY_SOCKET                       (0)
// #define MICROPY_PY_NETWORK                      (0)
// #define MICROPY_PY_ONEWIRE                      (0)

Maybe it depends on who first proposes a new board. I guess I am bit surprised that ONEWIRE was removed in this example. Could be time for a issue or another question asking specifically why ...

[sanbeg]

Oh, maybe they had something in that board and removed them. I don't see anything like that in the history for the nucleo-f411re. I opened a follow up issue, so hopefully that will help. #18524

[robert-hh]

There are at least three levels of configuration files:

py/mpconfig.h which includes port//mpconfigport.h
mpconfigport.h which includes /boards//mpconfigboard.h
mpconfigboard.h

The default's are set in mpconfig.h and are controlled by the MICROPY_CONFIG_ROM_LEVEL, which is usually set in mpconfigport.h with a default value set in mpconfig.h. The levels are:

#define MICROPY_CONFIG_ROM_LEVEL_MINIMUM (0)
// Only enable core features (constrained flash, e.g. STM32L072)
#define MICROPY_CONFIG_ROM_LEVEL_CORE_FEATURES (10)
// Enable most common features (small on-device flash, e.g. STM32F411)
#define MICROPY_CONFIG_ROM_LEVEL_BASIC_FEATURES (20)
// Enable convenience features (medium on-device flash, e.g. STM32F405)
#define MICROPY_CONFIG_ROM_LEVEL_EXTRA_FEATURES (30)
// Enable all common features (large/external flash, rp2, unix)
#define MICROPY_CONFIG_ROM_LEVEL_FULL_FEATURES (40)
// Enable everything (e.g. coverage)
#define MICROPY_CONFIG_ROM_LEVEL_EVERYTHING (50)

The default for STM32 is MICROPY_CONFIG_ROM_LEVEL_EXTRA_FEATURES, unless it is set differently for a board. MICROPY_CONFIG_ROM_LEVEL_EXTRA_FEATURES enables framebuf.

All of that does not explain why framebuf is disabled for the NUCLEO_G474RE board. You would disable for devices with small flash, but 512k is considered more a medium sized flash.

[sanbeg]

Thanks. I just download & compiled the source, without all those #define MICROPY_PY_ and that seems to compile and flash OK. I haven't tested too much on it, but it does add a few entries to the help output:

MicroPython 3f796b687b-dirty on 2025-12-06; NUCLEO_G474RE with STM32G474
Type "help()" for more information.
>>> help('modules')
__main__          builtins          json              select
_asyncio          cmath             machine           socket
_onewire          collections       math              stm
array             deflate           micropython       struct
asyncio/__init__  dht               network           sys
asyncio/core      errno             onewire           time
asyncio/event     framebuf          os                uasyncio
asyncio/funcs     gc                platform          uctypes
asyncio/lock      hashlib           pyb               vfs
asyncio/stream    heapq             random
binascii          io                re
Plus any modules on the filesystem