nuttx/Documentation/platforms
Marco Casaroli aeaf718fc9 rp23xx: Add /dev/timer driver on the TIMER0/TIMER1 blocks.
The RP2350 has two system timer blocks (TIMER0, TIMER1), each a free-running
64-bit counter incremented once per microsecond by the TICKS block (set up in
rp23xx_clock.c).  They are independent of the ARM SysTick that drives the OS
tick, so they are free for application use, but the port had no driver for
them.

Add rp23xx_timer.c, a NuttX timer lower-half that binds a block to a
/dev/timerN device.  It uses ALARM0 of the block, which matches the low 32
bits of the microsecond counter, to implement single-shot and periodic
timeouts with 1 us resolution and a maximum interval of 2^32 - 1 us (~71.5
minutes).  Periodic reloads are scheduled relative to the previous expiry to
avoid drift, but never behind the counter (an alarm set in the past would not
match until the 32-bit counter wraps).

Enable with CONFIG_RP23XX_TIMER (which selects CONFIG_TIMER), then turn on each
block independently: CONFIG_RP23XX_TIMER0 registers /dev/timer0 and
CONFIG_RP23XX_TIMER1 registers /dev/timer1.  A block claimed by the tickless
oneshot (CONFIG_RP23XX_SYSTIMER_TICKLESS) is excluded from these choices in
Kconfig, so the two features can be enabled together without colliding on the
same block or its alarm IRQ.

Tested on Pimoroni Pico Plus 2 (RP2350B) hardware with examples/timer and a
CMSIS-DAP probe.  The device registers as /dev/timer0; the ALARM0 interrupt
fires at the programmed period (verified over SWD at the configured 1 s
interval, not a busy loop), and the full path -- alarm match, the driver ISR,
the timer notification and delivery of the SIGNO to user space -- reaches the
example's signal handler and increments its counter.

Assisted-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>
2026-07-25 14:34:59 +02:00
..
arm rp23xx: Add /dev/timer driver on the TIMER0/TIMER1 blocks. 2026-07-25 14:34:59 +02:00
arm64 docs/raspberrypi-4b: Document baromonitor configuration 2026-07-20 21:00:46 -03:00
avr arch/avr/src/avrdx/avrdx_delay: add custom up_udelay function 2026-06-12 09:55:11 -04:00
ceva
hc docs/m9s12/demo9s12ne64: Migrate README.txt to RST 2026-02-12 10:43:53 +01:00
mips arch/mips/jz4780: Add USB host and display controller drivers 2026-07-24 12:17:35 +08:00
misco misco/lm32/boards/misoc: Migrate README.txt to RST 2025-05-08 03:04:04 +02:00
or1k docs/or1k: Migrate README.txt to RST format 2026-02-06 08:54:28 -03:00
renesas Documentation: PBKDF2 login docs, board Kconfig, and CI password 2026-07-21 20:19:14 +08:00
risc-v documentation: add Python defconfig to esp32p4-tab5 board 2026-07-22 17:58:01 +08:00
sim arch/sim: Add PTY mode for simulated UART 2026-07-25 15:03:56 +08:00
sparc
tricore arch/tricore: support tc4evb board. 2026-03-10 10:38:19 +01:00
x86 doc/qemu-i486: Add documentation about qemu-i486:vga_fb 2026-04-30 11:56:49 +08:00
x86_64 Documentation: add notes about TAP configuration for qemu 2025-12-18 11:39:54 -03:00
xtensa boards/stm32h7/linum-stm32h753bi: enable USB FS host, add lvglterm_kbda 2026-07-08 14:08:16 -04:00
z16 Documentation: update broken links 2024-04-10 15:17:53 -03:00
z80 style: Fix "the the" typo across the codebase. 2026-03-23 11:07:49 +01:00
index.rst docs: Fix duplicate toctree references causing build warnings 2026-06-03 15:02:22 +08:00