nuttx/Documentation
Marco Casaroli f0e4f61add arch/arm/rp23xx: Add RTC using the POWMAN always-on timer.
The RP2350 has no dedicated RTC block (the RP2040 one was removed).  Use the
POWMAN always-on timer instead: a 64-bit millisecond counter clocked from the
low-power oscillator, so it keeps running across warm resets.

Enabling CONFIG_RP23XX_RTC selects CONFIG_RTC and builds the driver, which
implements the simple up_rtc_initialize()/up_rtc_time()/up_rtc_settime()
interface backing the system clock (seconds resolution).  up_rtc_initialize()
sources the timer from the low-power oscillator at a 1 kHz tick and starts it,
preserving the value when the timer is already running.  POWMAN register writes
carry the required 0x5afe password.

Document the RTC on the rp23xx platform page: an "RTC" section explaining how
the POWMAN always-on timer is used (LPOSC clocking, the 0x5afe password and the
four 16-bit time registers, stopping the counter to reload it), with reference
links to the RP2350 datasheet Power chapter and the pico-sdk hardware_powman /
pico_aon_timer implementation the driver mirrors.  The same references are
noted in the driver header.

Assisted-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>
2026-07-26 19:21:34 +08:00
..
_extensions Documentation: port warnings_filter Sphinx extension from Zephyr 2023-11-28 09:18:29 -08:00
_static
_templates
applications docs/applications/txmorse: Document the txmorse application 2026-07-24 12:03:37 +08:00
components drivers/sensors: add LIS3DSH accelerometer uORB driver 2026-07-25 14:45:40 +02:00
contributing !arch/stm32: move stm32l1 and finalize the directory split 2026-06-24 14:54:44 -03:00
debugging Documentation: Add documentation of SCHED_DUMP_TASKS and SCHED_DUMP_STACK 2026-06-09 08:04:54 -04:00
faq !boards: Remove NSH_ARCHINIT and board_app_initialize 2026-05-02 18:36:46 +08:00
guides arch/arm/src/stm32: unify pulse count driver into common/stm32 2026-07-12 09:35:51 +08:00
implementation Documentation: Fix kernel module wording. 2026-07-05 19:43:23 +02:00
introduction WIP: Documentation: replace first person perspectives 2025-05-19 20:21:33 +08:00
logos style: fix typos 2025-04-30 13:45:46 +08:00
platforms arch/arm/rp23xx: Add RTC using the POWMAN always-on timer. 2026-07-26 19:21:34 +08:00
quickstart Documentation: fill in pass1 directory description in organization.rst 2026-07-06 10:18:42 -03:00
reference arch/avr/src/avrdx/avrdx_delay: add custom up_udelay function 2026-06-12 09:55:11 -04:00
ReleaseNotes Documentation: add NuttX 13.0.0 release notes 2026-06-25 19:50:07 +08:00
standards libc/unistd: add getgroups() 2026-06-24 14:55:11 -03:00
testing Documentation/testing: Document MemBrowse integration 2026-06-19 12:21:54 -03:00
.gitignore docs/tags: Introduce tagging feature to the documentation. 2025-04-29 09:18:25 +02:00
conf.py Documentation: conf: Ignore .venv 2026-05-29 01:26:21 +08:00
glossary.rst
index.rst docs/security: Add Security section to the documentation. 2026-01-06 02:17:20 +08:00
known-warnings.txt fs: Add VFS docs 2024-02-20 18:28:09 -08:00
legacy_README.md style: Fix "the the" typo across the codebase. 2026-03-23 11:07:49 +01:00
make.bat
Makefile doc: Improve sphinx build time + add autobuild help info. 2026-01-27 09:50:55 +08:00
Pipfile docs/plantuml: Add PlantUML support to Documentation build 2026-02-15 08:47:23 +01:00
Pipfile.lock build(deps): bump starlette from 1.0.1 to 1.3.1 in /Documentation 2026-06-18 12:49:49 -04:00
security.rst docs/security: Add Security section to the documentation. 2026-01-06 02:17:20 +08:00
substitutions.rst